Facebook has purchased most of drop.io, an online content-sharing service, but the social-networking giant sounds more interested in acquiring the company’s developers than its technology. Drop.io is a service that lets users create a ‘drop’ where they can share documents, videos and other digital content. The user can set a time for how long the drop will exist, decide who can view the content, set permissions for who can alter the content and share content in a variety of ways, including on Facebook.