[vibrant]

I've been working on a product also in this direction but it's more full featured and mature. It's called http://dynado.com and we're launching within a month (don't look at the design - the final main site isn't up yet).

It's basically a webmail where you can decide to either send somebody a task or an email. Everything goes through email though and you can send a task to anyone, even people from outside the system. They can then either collaborate via email or register to use the system themselves.

Of course it's integrated with an IM, file storage solution where you can attach those files, browse a stream of sent/received attachments. It also has a project tree and reports per-user or project, with really simple and integrated time tracking. AND it has a built in calendar with an innovative twist.

Basically it's an all-in-one business management tool tightly integrated with email in order to let you use the tools you know (email) but still capture all the knowledge and track all the tasks without switching to 10 different apps.