RiotNrrd:
I wonder if this slight difference in the English usage transfers over to "plaĉi"?

Surely not, english is very ambiguous, 'is pleasing' may be active construction with stress on present time like 'estas plaĉanta' or stative construction like 'estas plaĉa'. If the verb receives direct object, like 'me' then it is likely to be active construction. En esperanto there is no ambiguity, 'plaĉas' ≡ 'estas plaĉa', 'al' may be replaced by -n "if no confusion is to be feared" so it is not semantic change.

dimicĥp:

RiotNrrd:
I wonder if this slight difference in the English usage transfers over to "plaĉi"?

Surely not, english is very ambiguous, 'is pleasing' may be active construction with stress on present time like 'estas plaĉanta' or stative construction like 'estas plaĉa'. If the verb receives direct object, like 'me' then it is likely to be active construction. En esperanto there is no ambiguity, 'plaĉ' is adjective radical and 'plaĉas' ≡ 'estas plaĉa', 'al' may be replaced by -n "if no confusion is to be feared" so it is not semantic change.

OK now I'm just confused - I was going to argue that the ambiguity in English is still there in Esperanto, contrary to what you said, but now I can't see an ambiguity in English anymore, and that (contrary to what you said again ) English actually makes just as much sense as EO here - it all depends on the "al" or "to".

-It's pleasing me = Ĝi plaĉas min
= It pleases me = It pleases me

It's pleasing to me = Ĝi plaĉas al mi
= It is of a pleasing quality to me = It is of a pleasing quality to me

But now, I'm back to square one and wondering why the preposition is "al" as there is no movement... *headdesk*

ceigered:

dimicĥp:

RiotNrrd:
I wonder if this slight difference in the English usage transfers over to "plaĉi"?

Surely not, english is very ambiguous, 'is pleasing' may be active construction with stress on present time like 'estas plaĉanta' or stative construction like 'estas plaĉa'. If the verb receives direct object, like 'me' then it is likely to be active construction. En esperanto there is no ambiguity, 'plaĉ' is adjective radical and 'plaĉas' ≡ 'estas plaĉa', 'al' may be replaced by -n "if no confusion is to be feared" so it is not semantic change.

OK now I'm just confused - I was going to argue that the ambiguity in English is still there in Esperanto, contrary to what you said, but now I can't see an ambiguity in English anymore, and that (contrary to what you said again ) English actually makes just as much sense as EO here - it all depends on the "al" or "to".
-It's pleasing me = Ĝi plaĉas min
= It pleases me = It pleases me
It's pleasing to me = Ĝi plaĉas al mi
= It is of a pleasing quality to me = It is of a pleasing quality to me
But now, I'm back to square one and wondering why the preposition is "al" as there is no movement... *headdesk*

The ambiguity is in phrase 'is pleasing'. The phrase itself is the same for both stative and active construction. The active constructions carries temporal stress - 'is' stands for 'is pleasing now', the stative does not carry the stress, just as you described in your example phrases.
There is no such ambiguity in esperanto - 'plaĉas' is only stative construction, the temporal stress may be achieved by present adverb: 'estas plaĉanta', but i guess nobody uses that construction.
Let's go back to your phrases. They are not ambiguous, the specific sense (stative or active) may be resolved: if verb has direct object (me) then it's transitive and active. The phrase with 'to me' has no direct object, but indirect (with preposition 'to'), so it is likely to be stative.
How it is going in esperanto: the verb 'plaĉas' is always stative. In the first place it is intransitive, so it may have only indirect objects with prepositions. Since 'al' demonstrates generic direction (not just movement), it fits just fine for describing a subject the object pleases. It seems quite logical so the stable construction 'plaĉi al'.
The last thing is why '-n' can be used instead of 'al'. It is feature of esperanto grammar - a preposition may be replaced by accusative if no ambiguity arises. Usually there are no other indirect objects than 'al' to plaĉi, there is no direct object for it, so it remains clear if one replaces 'al' with accusative. It doesn't mean that it should be used everywhere, it's just possible. The replacement has no other consequences other that grammatical, the sense remain absolutely same.

Rightio, I think I get what you mean dimichxp! Last question then, what about saying "It pleases me" as a action, as in "The cat is pleasing me so it can get more food"? That was where I saw the ambiguity, because then "placxi" has two functions - one being "to be pleasing (estas placxa)" and the other being "to cause please or content with someone" (or something like that, at the moment I'm thinking something absurd like "felicxigxigi" ).

It goes without saying I'm gonna try and stick to "sxati" instead otherwise I'll probably stop mid-way during the conversation to have a big think about the logic behind what I'm saying

(Edited a few english errors and made "estas placxi" to "estas placxa")

ceigered:

Plaĉi IMO can seem like a strange verb to speakers of English, because while it is officially intransitive, as if it referred to an inherent quality, we can hardly apply it in practice without an indirect object. Perhaps it would be better if it were transitive. But, for better or worse, it is intransitive, as the [url=http://www.akademio-de-esperanto.org/akademia_vortaro/index.html?serchas=1&tt=1261482201&ve=plaĉ&vg=-&vr=jes&vp=jes&vs=jes&vm=jes&vl=jes&vf=jes&vk=jes&va=1&tradukoen=1]Akademia vortaro[/url] indicates, so we're stuck wth it.

There are other verbs like that, as PMEG points out like manki. See also the section Spertanto, sentanto.

ceigered:Rightio, I get what you mean dimicĥp! Last question then, what about saying "It pleases me" as a action, as in "The cat is pleasing me so it can get more food"? That was where I saw the ambiguity, because then "plaĉi" has two functions - one being "to be pleasing (estas plaĉi)" and the other being "to cause please or content with someone" (or something like that, at the moment I'm thinking something absurd like "feliĉiĝigi" ).

I don't really understand your problems with plaĉi. I think dimichxp very good described the use of this word. You don't always have to use this word, you can use other words to describe what you want to express:
I like this dress - Tiu vesto plaĉas al mi
I am fond of this guy - mi ŝatas tiun ulon
I like this cat so it can get more food - Tiu kato plaĉas al mi, do ĝi ricevu pli da manĝaĵo
The cat is pleasing me so it can get more food - Tiu kato ĝojigas min, do ...
aŭ
tiu kato feliĉigas min ...

Obviously the problem is not the word plaĉi, but the english word to please.

By the way: estas placi is not possible, perhaps: estas plaĉanta? Vidu la mesaĝon de dimichxp.

horsto:
I don't really understand your problems with plaĉi. I think dimicĥp very good described the use of this word. You don't always have to use this word, you can use other words to describe what you want to express

Well I almost always use ami/ŝati or something like that, and I don't have any real problems with "plaĉi al", I'm just finding the nuances between "plaĉi -n" and "plaĉi al" confusing, to me I can barely see a difference yet I get the feeling from responses here that there should be a difference. In fact, I can't help but think "plaĉi -n" is more correct as "plaĉi al" still seems to indicate to me some form of movement, which seems superfluous.

Obviously the problem is not the word plaĉi, but the english word to please.

Well, actually, this is what I don't get. In Esperanto, I don't see any reason for why "plaĉi al" and "plaĉi -n" are different, and in English it's the same for me, I can't see a difference, but for some reason I feel as if I'm wrong and there should be a difference (and saying "it is pleasing to me" doesn't really make sense to me, I mean, I understand it, but the logic behind that construction seems a bit odd).

By the way: estas placi is not possible, perhaps: estas plaĉanta? Vidu la mesaĝon de dimicĥp.

Ah thanks for pointing out my typo, I meant "estas plaĉa" "estas placxi", deary me, what was I thinking!

ceigered:

Obviously the problem is not the word plaĉi, but the english word to please.

Well, actually, this is what I don't get. In Esperanto, I don't see any reason for why "plaĉi al" and "plaĉi -n" are different, and in English it's the same for me, I can't see a difference, but for some reason I feel as if I'm wrong and there should be a difference (and saying "it is pleasing to me" doesn't really make sense to me, I mean, I understand it, but the logic behind that construction seems a bit odd).

I'll try to repeat what dimichxp explained. In Esperanto every verb can be transitive, intransitive or reflexiv. If a verb is transitive or not, this decides the creator of this verb. It's certainly an interesting question why he made this decision. In the case of plaĉi Zamenhof decided that this verb is intransitive. Therefore, if you want to specify the person, you have to use an indirect (dative) object, which is built in Esperanto whith the preposition al.
That's all. The correct form therefore is:
tio plaĉas al mi
But there is also a common rule that allows to simplify every form like:
verb + preposition + object
per
verb + object - n
Therefore it's also possible to say:
tio plaĉas min
but this form has exactly the same meaning, it's only a more simple way to say that.
This form is of course only allowed if the sentence is still understandable, you can't simplify f.e.:
li donis libron al ŝi
per
li donis libron ŝin

Miland:while it [plaĉi] is officially intransitive, as if it referred to an inherent quality, we can hardly apply it in practice without an indirect object.

Actually 'plaĉi' can and frequently is used without any indirect object and there is no need at all to show who something is pleasing to. Additionally, plaĉi is not used "as if" it referred to an inherent quality; that is its very meaning, as well as the reason it was deemed intransitive in the first place. Here are a few examples from Tekstaro and the definition for 'plaĉi' at Reta Vortaro:

Quo vadis? - Dua parto
Kaj vi estas certa, ke tio plaĉos en Aĥajo?

Kruko kaj Baniko el Bervalo
Post tenispaŭzo plaĉas reko el elektemulo.

Artikoloj el Monato
Ne plaĉas la pluva sezono.
Kial ne uzi la etnonomon “eŭskoj” anstataŭ “baskoj”, se ne plaĉas (prave) la PIV-a “vasko”?

Internacia krestomatio
La plej juna Roccatagliata edziniĝas antaŭ la fratinoj; ŝi faras malbone, tio ne plaĉas en la provinco.

Fabeloj de Andersen 4
Lia vigla karaktero plaĉis ĉe la unua vido, li tamen ne multe faris, li havis tro multe da festoj.

Reta Vortaro, Zamenhof quote
se ne plaĉas najbaro, ne plaĉas lia faro

Every verb can have an object if its sense permits this. I find the whole transitivity thing pretty weird - you just have to learn the correct meaning of each verb, and if that meaning allows an object, you're allowed to use it.

Of course you can say "plaĉi min" and "aparteni min", just as you can say both "helpi min" and "helpi al mi". It's just that the form with "al" is more common, so you're more likely to be understood using "al". That's why I tend to use "al" here (although this may also come from native language influences - as horsto explained, in German you use the dative with "gefallen" (to please) as well as with "helfen" (to help), so I use "al" with these verbs in Esperanto).

See also a Lingva Respondo by Zamenhof where he explains this.

La esprimo “estu timata” estas uzita tute bone kaj regule. En la rusa lingvo la vorto “timi” ne havas pasivon, sed tio ĉi ja tute ne montras ankoraŭ, ke ankaŭ en Esperanto ĝi ne devas havi pasivon. En ĉiu vivanta lingvo estas permesita uzi nur tiujn formojn, kiujn aliaj personoj jam uzis antaŭ vi; sed en la lingvo internacia oni devas obei sole nur la logikon. La logiko diras, ke ĉia verbo povas havi pasivon, se nur la senco ĝin permesas. Sed en la verbo “timi” la senco tute bone permesas pasivon, kiel en aliaj verboj. Ĉe la timado ni havas ĉiam du personojn aŭ objektojn: unu, kiu timas, kaj unu, kiun oni timas, aŭ kiu estas timata. “De l' malamikoj vi estu timata” signifas: ke la malamikoj timu vin (= je vi aŭ antaŭ vi). Vere, ke en la rusa lingvo oni diras ne “timi lin”, sed “timi de li” sed tio ĉi estas aparteco de la rusa lingvo, kiu tute ne estas deviga ankaŭ por ĉia alia lingvo. Jam la senco mem permesas tute bone uzi la verbon “timi” kun la akuzativo (en tia maniero ĝi ankaŭ estas uzata en multaj lingvoj, kie ĝi tiel ankaŭ havas pasivon); sed se la senco ĝin ankaŭ ne dirus, ĝin diras ja tute klare nia gramatiko, laŭ kiu en ĉia duba okazo oni povas uzi la prepozicion “je” aŭ la akuzativon sen prepozicio. Eĉ de vortoj, kiuj per si mem ne postulas la akuzativon, vi povas en nia lingvo libere ĉiam fari pasivon, se nur la senco de tiu ĉi pasivo estos komprenebla. Tiel ekzemple en la versaĵo “Al la Esperantisto” estas ne malregule uzita la esprimo “la celo estos alvenita” (= oni alvenos al la celo).

Translation:
The expression "estu timata" (=be feared) is used completely well and regularly. In Russian the word for "to fear" doesn't have a passive, but doesn't at all show that in Esperanto it can't have a passive either. In every living language it's allowed to use only forms others used before you, but in the international language you have to obey only logic. The logic says that every word can have a passive if only its sense allows it. But with the word "to fear" the sense completely well allows a passive, as with other verbs. With fear we have always two persons or objects: one who fears and one whom one fears, or who is feared. "De l' malamikoj vi estu timata" (=by the enemies be feared) means: that the enemies shall fear you (timu vin = timu je vi, timu antaŭ vi). Indeed, in Russian you don't say "fear him" but "fear from him" but that's specific to Russian and not at all required as well for every other language. Already the sense itself allows completely well to use the verb "timi" (=to fear) with the accusative (in that manner it's also used in many languages, where it also has a passive); but if the sense doesn't say it either, it says at least our grammar, according to which you can, in every case of doubt, use the preposition "je" or the accusative without a preposition. Even from words that don't by themselves require the accusative, you are in our language free to make a passive, if only the sense of this passive is understandable. That way, for example in the verse "To the Esperantist" the expression "la celo estos alvenita" (=oni alvenos al la celo) [=the goal will be reached, one will reach the goal] isn't used irregularly.

I believe that this should be convincing that there's nothing bad about using "plaĉi min".