Program to put tags (not ID3) on MP3s

I was thinking of this for myself some time back,
Had found the TaggTool.

Tagg only stores pointers to your files and will never change or move files. Tagg does allow you to copy files but the original file is left untouched. When Removing Tags remember that only the pointer to the file is being removed from Tagg's database and not the physical file.

But, Lately, I find Locate32 is a better way for me.
The best part is -- it allows you to create databases of specific search scopes
(think of it as customized 'windows search index' files).

Locate32 is software which can be used to find files from your harddrives and other locations. It works like updatedb and locate commands in Unix based systems. In other words, it uses databases to store information about directory structures and uses these databases in searches. The use of these databases provides very fast searching speed. The software includes a dialog based application as well as console programs which can be used to both update and access databases. Supported operation systems are Windows 98/ME/NT4/2000/XP/Vista.

Songbird with the Tag Cloud Generator add-on looks like it will do exactly what you are looking for.

I agree with Andi, but I would you use the comment-field.

Je simply add ie. ;nostalgic;ballad;carmusic;whatever....

You could get more tags in the ID3-tag if you use short codes like ;Q;car;w.ever;...