Why she matters: Facebook and MySpace get the attention, but Bianchini's Ning might be the most exciting thing in social networking right now. Instead of simply encouraging people to join one ubernetwork, Ning lets users create their own mini communities, complete with customizable layouts, profiles, blogs, videos, and ads.
Just as blogs changed the Web by turning ordinary folks into pundits, Ning could do the same for community. Bianchini wisely kept Ning's code mostly open, enabling it to add new features at will. Next up: helping Ning fans dress up their networks with group calendars and wikis.