Welcome to the Men On The gay porn links directory.
In the context of gay sex sites, it generally means performers who are not official porn stars.
It's a broad definition including guys who are first-timers, aren't as experienced in gay sex or being on video, aren't paid a lot; reality studs, guys who have less perfect bodies or appearance, guys who do gay porn on the side or just for fun, anonymous or unnamed guys, etc.
Check out these guys popping their porn cherry at Boyfriend Nudes, All-American Heroes, and Str8Boyz Seduced.
This is a general theme for content that stars Amateurs (see above).
The category can include reality sites, voyeur sites, first-timer sites, international sites, audition sites, straight boy sites, and a lot more.