Yup, Windows Media Player sorts them into categories "they" see fit, so you could have 2 bands you'd categorise as indie, and they could go into rock & indie for example.
Also, you need an MP3 tag editor to amend the information for albums you "found on the floor", otherwise if it just has a folder name to work from, it's not clever enough to work out the artist/album and song names.
If you already have the tag info like...
Artist : Kaiser Chiefs
Album : Employment
Title : I predict a riot
Then it can find it straight away and sort it, but otherwise it can be a bit shit, especially with new albums that have just been released, or stuff that isn't very popular.
Also you are sending info' to Microsoft about the music you have "found on the floor", and it all depends if you're bothered about them knowing that or not.
What it really comes down to is that people who rip MP3's are uttelry lazy, and don't rename them in a standard that everyone uses.
Since Napster was closed, nobody has a clue how you should name files, which is a shame, as people used to have to name the files appropriately for others to know what they are to download them.
Basically internet users are a messy bunch of fuckers, and nobody seems to care about MP3's being named to a set standard.
That's why it's taken me the best part of 50Hrs to go through every one of my tracks and edit them to a set standard.
