Matt Cutts om bland annat .IO och .CO
http://www.youtube.com/watch?v=QCozweHGTk0
"...There's a lot of startups that have been using .io, which is the TLD for the Indian Ocean, I belive."
"...So, .co, witch used to be, I think, Colombia, might be more generic now where everybody's using it as if it is another .com."