ID3 Tags are special meta information that contains information about artist, title, album, etc. Mp3 files not always contains ID3 Tags. Anyone can add or change ID3 tags(in WinAmp press Alt-3 to do this). But if WinAmp(or other player) shows the artist and title for mp3 file(not something like track01.mp3) then thi file has filled ID3 Tags. I just want to add that the Abee Mp3 Duplicates Finder can extract artist name and title from filename, if ID3 tags are empty.