Renniks my information is just google based so I'm not 100% on that. It's an interesting one though as there is the slight worry people will think it's a typo and you've forgotten the 'm' or '.uk'. I suppose it depends on how much they take off in the long run as to whether it becomes common knowledge as a domain suffix or not.
Give them a miss, there's been tons of new domain extensions that have never taken off, and I think this will be another in the long list!!
.co is the country code for Colombia, so without some very strong signals to the search engines that your site is a UK based site/business, then I imaging they will assume it's relevant to Columbia. As for .co representing company, community, etc that's just the domain registrars trying to cash in on a rush for a new extension!
Yeah along with server placement it does help to get the .co.uk one if your site is localised to UK residents.
The columbian one will be both the .com.co together wont it?
Especially if just .co on its own has only just become avaliable, what did the coloumbians do before?
But I agree with Greg its just the registars trying to cash in.
If compaines just stuck to .com, networks just stuck to .net, blogs just stuck to .info then .co could be benefitial for communities but as there is no constraints on which one you get, get the cheapest and .com if you can as everyone just assumes your site will be .com even if your not a company.
I would love to see registars making you have the correct extention for your site, IE: making you send proof you have a registered company to be able to claim the .com as IMO it would make the internet a much easier place I reckon. But hay.