Dropbox has joined the growing number of file-sharing applications that connect to Facebook so that people can share content with friends.

This saves Dropbox users from having to input the email addresses of intended recipients of shared content.

Dropbox differs from from other file sharing apps, or at least the ones that connect to Facebook, in using folders for people to save things into and read from.

Other content-sharing apps connected to Facebook include:

• Pipe, a startup launching this week for large-sized file transfers;
• ScanDrop for Apple-based content;
• Microsoft’s Docs.com, which taps into Facebook groups; and
• Scribd, which has enjoyed larger numbers of users than the others, at least until recently.