Tagline: None for either.
Clientele: Well, we know who the inmates are. But we can't imagine who'd want to write to them, aside from other inmates. You could just become pen pals, or you might find love. WomenBehindBars, for example, claims to have fostered 38 marriages in its 12-year existence. Special features: Most of the ads include the prisoner's release date, so you can make long-term plans, but neither site provides the details of each conviction. Inmate.com also features original convict art and writing, such as "The Continuing Saga of Icicle Bill and Tommy Two-Head," a buddy crime saga.
Clientele: Women who want breast augmentation, and men who want to help them. Basically, the women accrue money for surgery by chatting with the male clients.
Special features: Plenty of chatting, and for guys willing to pay, customized photos and videos of the girls (provided they agree to the requested poses/outfits/settings). Also, a contest in which a lucky woman can win a free boob job!