Each country has an assigned Top Level Domain like .uk for the United Kingdom, .br for Brazil, and .cn for China. It has become fashionable for websites geared towards local content to use the appropriate TLD in their URLs to emphasize their orientation and help buoy rankings in search results. However, as one user has observed, using the country code does not always produce an automatic advantage over generic TLDs. Many .com sites are in fact ranking so high up in many UK search engine result pages. Google’s Matt Cutts explains why in this video.
Essentially, he says that as Google becomes more confident in identifying local content, they get more willing to add sites that do not bear the country code at all. The primary determining factor in search rankings is relevance to the user and not the domain name. After all, there are several sites that use a country’s TLD without containing any relevant local information. A good example would be .tk, which is native to Tokelau but is being used by a wide variety of websites all over the world as a free service. Some local companies, on the other hand, use .com for its simplicity and name recall.
Video Link:
Why are .com sites ranking highly in UK SERPs? –