Alibris is the other big second-hand online book marketplace; AFAIK it's still a private co. (not that that's necessarily a guarantee they're any better than Amazon of course), and lots of book dealers will list stuff on there as well as on ABE.
@Thrustvector started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
Alibris is the other big second-hand online book marketplace; AFAIK it's still a private co. (not that that's necessarily a guarantee they're any better than Amazon of course), and lots of book dealers will list stuff on there as well as on ABE.