Just started using Writely a couple of days ago and I have to tell you that I really like it.
For those of you not familiar with it, Writely is an online word processor (think Microsoft Word on the web). It has all the basic functionality you'd expect... and it's free (does anyone know if it is to remain free?). One of the really cool things is that Google purchased them so I didn't have to jump through hoops to set up my account, it recognized my gmail account and I was in and writing in seconds flat (bravo!).
My only negative feeedback, and this is minor, is the "New" link located at the top left... I didn't notice it at first. I didn't know how to create a new document, and it took me a second or two to find it. I would say that creating a new document is probably one of the top two or three tasks people will have, so it should be featured a little more prominently.
Other than that I think it is great. You can save documents in various formats (Word, PDF, HTML, etc), you can collaborate, view revision history, check your spelling, etc.
I wrote the last post (Culture Code) and this one in Writely!
I highly suggest checking it out.
What do you think? Have you tried Writely? What are your favorite features?