MM/mm stands for meimei (妹妹, literally, “little sister”) stands for girls, chicks, hotties, or whatever term you choose. Mainstream sites in virtual China are rife with sexualized pictures and videos of women. It would be like having Playboy cover shots and links to porn videos on AOL, MSN, or Yahoo.
The photo above comes from the #4 most popular photo series for March 17 2006 on Sina.com’s BBS site. The series of relatively tame “art photos” of bathing starlets received 60,004 hits in 24 hours.