OT: Web Based Collaborative Diagramming Applications

[Sivakatirswami]

  I'm looking to adopt a web based collaborative diagramming tool.

gliffy.com of course is touted as the "world's best" and from what I see 
there is a lot to be said for chosing Gliffy.

But, before just jumping on the nearest big bandwagon, I thought to ask 
here if anyone knows other web based collaborative diagramming apps that 
they really like and are easy to use and meets there needs?

Reply here or off list...

Thanks
Sivakatirswami