• Silverlight could be an issue, the adoption rate isn't that great so the majority of visitors would have to install a plugin to be able to do anything — people get turned away from sites because of a slow loading page, so being prompted to install a plugin may be enough for them to bounce back to where they came from. Plus of course a lot of corporate environments have a ban on installing new software, and a lot of mobile devices (iPhones, etc.) don't even have Flash, so Silverlight is a long way off...

• Black — arrggg! Personally I hate websites which have a colour palette ranging from #ccc to #000! They even disorientate me a bit…I think! It may just be me, but somehow I doubt the rest of the world loves such a dull colour.

However it's a very impressive app, you can tell you [guys (?)] have put a lot of work into it, and I wish you the best of luck — if I needed such a product I'd be MORE than willing to pay for Colaab! :)