This is really quite cool. A few thoughts:<p>- When I click "claim your identity," it should take me to the create an account tab. At this stage, why not make that the default tab?<p>- I'm no designer, but the tan / pink / fleshtone color isn't working for me. If it's dear to you, ignore me. I just redid my site's color scheme because people told me it looked like a developer's hobby project, not a business tool. I used <a href="http://kuler.adobe.com/" rel="nofollow">http://kuler.adobe.com/</a> and was pretty happy with results. On a similar note, anti-alias your logo and save as a png (with a background if you don't want to alienate the ie6 crowd).<p>- The killer use of this, IMHO, would be the ability to integrate your technology into an already existing block of text hosted elsewhere just by dropping a line of js into the page (like <a href="http://www.apture.com/" rel="nofollow">http://www.apture.com/</a>). I know that's not a tiny feature, but I imagine a lot of bloggers would love to offer this sort of "live editing feedback" on their blogs (and might be a paying audience). Either that, or provide tools to "publish version to blog" and have integrations for popular blog software.<p>- More on screen help. This is really hard, particularly for an interface that requires users change their behavior. We're so used to looking at text and assuming it's static that we need some tooltips or something that says "here's how to use _this_ text." Maybe something that can be dismissed once a user has seen it (that's what we're doing), but don't rely on your document creator to add directions on how to use revizr in the document directions. They're already advocating for you by using your tool; don't make their job any harder by making them explain it to people they want to use it with.<p>- "Tag the new version" -- tags are cool and useful and keep things organized, but why do I get prompted to tag my version when I advance to a version? I'm trying to do one thing and the software is asking me to do another.<p>Overall, it's a really neat app; a mix of google docs, wiki, and document publishing, with better change documentation and integration control tools.<p>--<p>Hope that helps, and good luck!