I have just spent a bit of time playing with iPlotz, which is a new web-based wireframing and collaboration tool for web designers.

It doubles as a tool for creating quick sketches of how web sites are going to look, as well as a kind of project management tool that lets you track tasks and assign them to people, etc.

It has a very nice Flex interface, allowing you to quickly drag standard controls onto a page and build up a visual layout with a funky sketch look.

www.iplotz.com

I think that this really fills a need, and it seems like a very simple and easy-to-use product.

I would like to see them use this tool as a basis for an complete online document collaboration system (which I feel could be much better than Google Docs).

Introduction to TextFlow