Your information, please.
Why all this information?
Because we need it! Honestly!
Your email address is your user name. So there.
We ask you to supply your Last.fm information in order do more things on Tagfriendly (e.g.: scrobbling).
We at Tagfriendly realize how sensitive data is in this day and age and promise to never share your information in any way. Period.
There are some Last.fm features that do not require a password, so if you're more comfortable only giving us your Last.fm user name, we understand.
After all, it is your information.