Appjacked!

When entrepreneurs Ade Olonoh and John Wechsler founded Formspring, they likely didn’t intend to create a haven for sexting-prone politicians. And yet, thanks to Anthony Weiner, that may well be its legacy: the Q&A-based social network is now known as the place where “Carlos Danger” solicited a 22-year-old woman and potentially torpedoed his mayoral campaign.

Of course, Formspring is not the first app to be co-opted for a purpose its creators did not intend. Such an event is often a rite of passage–and a valuable one at that. Twitter’s hashtag feature, for example, was dreamed up by early adopters. And when Fabulis failed as a social network for gay men, it changed its name to Fab.com and pivoted toward retail, one of the few sections of the site users were embracing. Now it touts more than 10 million users.

Not all repurposing is welcome. Just ask Facebook, which spent the past six months deleting some 7 million fake accounts created by users to artificially boost brand popularity (among other things). Here we highlight how companies responded to five recent appjacks–for better and for worse.