Dropbox's next play is yet another collaborative writing tool

If there's one space in the software world that's crowded, it's the document collaboration market. Google, Microsoft, Evernote, Box, Quip and a whole host of other companies all want to get a piece of the pie.Dropbox just threw its hat in that ring Thursday with the public beta release of Paper, the simple, collaborative and cloud-based text editor that it previewed in Engadget and Wired. A document in Paper starts simple: Users only see a title field and a body field when they open a