Internet domain registrars began selling .co domain names on Tuesday, and some of the 11 virtual-real-estate sellers report seeing plenty of demand.

Most domain retailers are selling this first batch of .co names for about $30 per year. Dot-com domains generally go for $10 or so, but the list of memorable .com’s is ever-dwindling.

Major U.S. vendors of Internet land, including Go Daddy in Scottsdale, Ariz., and 1&1 Internet in Philadelphia, are advertising .co’s prominently on their home pages. Australia’s Melbourne IT reports on its Twitter page “a massive success with .co with most customers getting their choice of .co domain name.”

Twitter, the San Francisco company, was among the earliest adopters with T.co, which the company is using for its URL shortening service similar to Bit.ly. Twitter took possession of that Web address before .co names were being widely sold.

Other companies are less enthusiastic about the new Internet subset. Some feel compelled to pay high prices to secure their brand names from domain squatters looking to capitalize on an opportunity.

“.CO domain is yet another reason to be screwed by domain squatters,” read a tweet by Ben Huh, the chief executive of the Cheezburger Network of blogs that includes Fail Blog and the site that launched the Lolcat phenomenon.

Online retailer Overstock.com said it paid $350,000 for O.co and “related URLs.”

— Mark Milian
twitter.com/markmilian