Posterous entered the world when self-described "Apple fanboy" Sachin Agarwal, a student of stellar product design, left his cushy job at Apple after he felt a "burning need" to build a better way to share photos and content on the web.

The startup was first embraced by early adopters for its simplicity, but was often pitted against the trendier, higher traffic-generating Tumblr. Three years later, Posterous is now developing its own identity thanks to its wildly popular new group sharing features.

"What we're finding is that Facebook's network has gotten too big," Agarwal says. "It's because they are so successful that people feel like they don't have easy controls to indicate who can see what. It's because of their success that we have this opportunity [with groups]."

Design