I picked up a few issues of "Practical WEB PROJECTS", (an excellent UK based publication, BTW), a couple of years back and saw clearly how co.uk advertising dominated throughout, which shouldn't be suprising for a magazine that has very little non-Europeon distribution. (There were only a couple of copies that made it to the magazine rack at a very large computer store in LA.) What still surprises me, is the relative lack of awareness in the US of exts other than .com, .net, and org.*
* However, it does seem that .tv and.biz , have been more visible and are making inroads. Ironically, co.uk, other cctlds and, possibly, .eu may impact the .us cctld in the US more than anything else, as the general US population slowly comes around to the realization that there are alternative namespaces.