Back in August, Techcrunch wrote a nice summary of the product:
Imagine Word, but as an ajax browser application that was free. And allowed tagging of documents. And you could set reader permissions for each document you create and allow others to edit the document, or just read it. That’s what Writely is.More information can also be found at the Writely Blog.
It is a very functional word processor with most of the bells and whistles you’d expect - a range of fonts and styles, embedded images (up to 2 megs each), spell checker, etc. It has a fantastic wysiwyg editor. It also has an option to upload and/or save in Word format.
Writely built the core feature set with an ajax UI, and then they went a step further and added some cool web 2.0 stuff. In addition to naming a document, you can allow others to edit it, or allow them read-only status. Documents can also be tagged for easy searches later.
Writely is a highly specialized niche application built with ajax. Ajax allows this (and other applications) to act very much like desktop apps. Stuff like this must get Microsoft’s attention…How long will it be before a full suite of platform-independent ajax-enabled office applications becomes available? If all you need is a browser to open and edit these documents, the huge network effect enjoyed by Microsoft Office could simply vanish.