<< Would posting a link to my MP3 FTP be against the forum rules? >>
yes.
because unless you implemented a verification system, you couldn't tell if the person downloading the MP3 already owned the song or album (unless its your own personal music, and you own the copywright to it) and that would be against the RIAA laws 🙂 and Anandtech doesn't want to be sued.
however...
If its songs you make personally (i mean you're a musician) i don't see why it would be.