i noticed that if "Write ID3v1 tags to mp3 files" is unchecked the metadata written to the files are only readable by foobar (which i think is great), so is this metadata like the one in vorbis? where is it written (beginning or end of file)? and if this kind of metadata could be written to files why wasnt it used before??

tia

Foobar writes APE Tag v2 at the end of mp3 files if option you metioned is unchecked.

afaik foobar allways writes APE V2 tags and only adds ID3v1 tags when the option is checked.