You can probably already think of a bunch of different ways to collaborate with your web-working co-workers on editing a piece of text: emailing drafts, wikis, instant messages, online word processors like Google Documents or Zoho Writer. DoingText is a new entrant in this crowded field, hoping to gain some interest by making the process as low-friction as possible.
The idea behind DoingText is simple: you launch a new discussion by pasting a chunk of text to their site. From there, you get a dedicated editing window that lets you make changes. The editing window understands the Textile markup language, so adding things like bold and italic and hyperlinks is simple.
With the discussion you also get a URL that you can share with anyone. You can make the URL password-protected if you want. Anyone with the URL (and password, if necessary) can edit the text too: the system tracks revisions, and allows for comments and color-highlighting.
When the text is in a final state, you can download it as text or PDF, or create an online presentation from it. Things work smoothly, and as long as you don’t mind editing in a markup language, it’s easy to figure out how DoingText works. Currently the site is in closed beta, though it only took me a day or two to get invited after applying.