another Google Beta [purchase]

Google recently bought Writely a web based collaborative document editor. You migh think, 'Yawn, another wiki knock-off,' but this thing looks interesting. They list the following capabilities:

• Upload Word documents, OpenOffice, RTF, HTML or text (or create documents from scratch).
• Use our simple WYSIWYG editor to format your documents, spell-check them, etc.
• Invite others to share your documents (by e-mail address).
• Edit documents online with whomever you choose.
• View your documents' revision history and roll back to any version.
• Publish documents online to the world, or to just who you choose.
• Download documents to your desktop as Word, OpenOffice, RTF, PDF*, HTML or zip.
• Post your documents to your blog.

Now they also say you can simultaneously edit a document with your colleagues and that sounds cool. If you and your fellow editor collide you get a pop up warning--and I guess you arm wrestle over who's right. Sounds interesting; I wonder what counts as colliding? Do you have to simultaneously edit the same word? What if you are simultaneously editing the same sentence? couldn't that cause problems?