Last spring document sharing portal Scribd launched an impressive new HTML5 engine that can render the site’s millions of documents in the browser, without Flash. Now fellow Y Combinator alum Crocodoc is launching its own HTML5-based document viewer that’s very similar to Scribd’s, but with a few key improvements, including the ability to actually annotate these documents in the browser. In other words, you now have one less reason to fire up your bloated copy of Adobe Acrobat. You can check out a document that’s been rendered using this HTML5 technology right here.