everything you never wanted to know, and were afraid to ask
Many people use id3 tags, and don't know, or want/need to know, what they are. basically, mp3s, and many other formats, use id3 tags to attach "metadata" or info about a data file, within the file itself. that way the info travels with the data. text strings are the most common id3 info, things like song title, artist name, or album title for example. but other things can go in there as well, like artwork.
you can read about the id3 standard here: www.id3.org
the original, and now obsolete standard was id3v1 and id3v1.1 ...while you can still use these, and some very old devices / software will only work with them, best practices is to not use them and strip them, unless you need them for some specific reason. they are limited in what info they can contain, and how many characters you can put into them. so a song title for example, can only be 30 characters and there is no "frame" or field of entry at all for "Album Artist."
it is best to strip v1.x tags, because otherwise the data in them may become divergent with hopefully present id3v2.x tags, (and ergo confuse some software or devices, or even users! ;)
id3v1.x tags are stored at the end of a file.
id3v2.x tags are now the de facto standard for mp3 and many other lossy file types. id3v2.3 is probably the best supported, but 2.2 and 2.4 are also out there. 2.4 has some advantages in abilities, but is not widely popular nor nearly as well supported as 2.3
these tags support many more "frames" or fields of info, and without the character limitations.
id3v2.x tags are stored at the beginning of a file.
winamp recommends only using id3v2.3 unless you have a special, specific need to use something else. you can configure winamp to not create id3v1.x tags by going to options > prefs > plugins > input > in_mp3.dll > configure > id3 tags tab.
id3 file types include:
mp3, MP3Pro (dead format), MPC (MusePack), AAC
Winamp and id3
in most cases, winamp will handle your tags for you. it has "autotag" features, and will simultaneously update both v1 and v2 tags, or add them. you can also use the powerful ML to do edits or mass edits manually. be sure to investigate the prefs controlling metadata, especially on the "Watch folders" prefs dialog. power users will want to turn off all "metadata guessing" winamp does, which you do in two places in watch folders, and they will also want to turn off "use artist as album artist." doing these things are important to be able to see the reality of the data in the tags.
however, there are times a powerful tag editor is needed. the best tag editor out there, is mp3tag, which thankfully is also free but does solicit donations. www.mp3tag.de/en
mp3tag can scan for and repair "bad" malformed tags in files, as well as mass strip other tag types out of files. it can also, via a cut and paste operation, turn all tags, like id3v1, into proper id3v2.3 tags, (and remove the other tags).
when winamp won't do the trick, mp3tag almost always does. and like winamp, it works with nearly all file and tag types.
there are other tag types, such as APEv1 and APEv2, Lyrics3, and Vorbis. but since this forum title is "id3 tagging info" we will not address them here. winamp recommends best practices is to remove these types of tags from mp3s anyway, unless you have a specific need or desire for them to be present.