Databases for mp3 tracks

Probably this is silly question, but I didn't see the answer yet...
does anybody know any database where people could share their mp3 tags? It should be very simple - identify mp3 by md5 checksum of the 'audio'-part, and store information submitted by users... Or things like this will never exist? (but why not...)

Well, I do have thought of such a Mp3tag supported tag database too.
There are many many Mp3tag users out there in the world whose daily work is tagging all around what they can tag :-), with other words, they all do value adding work, making the pure mp3 file more valueable by adding additionally informations, so that all efforts combined into one database will offer a mighty valueable database of proofed musical background informations.

But there are some problems.

Identifying mp3 by md5audio checksum will not work in all cases, ... say, it will be magic if it would be able to find almost one hit.
I want to say that md5 hash and md5audio hash are pure technical values, a number that describes the state of this data, of the audio stream, in this moment.
In the moment you have manipulated the audio data, e.g. by 'removing silence at front or at end of a song' or by 'make louder' or maybe by hard changing frame values by 'Mp3Gain', the md5audio checksum will be changed too. Change only one bit then md5 has changed too. And do not forget that md5 is not collison free.
Therefore a md5audio hash cannot be used to identify two similar sounding audio streams. The comparing of md5audio hashes to get a hit only works on totally identical streams.

I think the Musicbrainz identifying method is the best development today in this area. I think they use some sort of spectral filtering, beat detection and other magic dust to build a fingerprint for the specific mp3 file. Once they have their database filled you might be able to detect all mp3 audio files which have ever registered by Musicbrainz at your fingertips.

You may realize that all people coming into this forum, all resp. each of them, have some imagination of 'tagging beauty' in their mind. There are some people who love uppercased words, there are others who love all words written in lowercase, and there are people who love mixed cases. All personal requirements together will be a knock out for a shared tag database for Mp3tag users.