ICANN (Internet Corporation for Assigned Names and Numbers), the organization responsible for managing the Internet's domain name system, may be facing a challenge to its legitimacy in Congress.

The US House Commerce Committee, concerned about the process ICANN used to select seven top-level domains, is holding a hearing Thursday to investigate whether the organization is thwarting competition by limiting the number of additional domains to the ones it chose.

Critics are expected to ask the committee to push for the domain selection process to be re-opened.

Inadequate ICANN is facing criticism from the American Civil Liberties Union (ACLU) and other groups, which sent a letter to the Commerce Department last month asking the agency to withhold approval for the new domains and threatening legal action if that doesn't happen. In the letter, the ACLU and its backers charged that ICANN's selection process was "woefully inadequate by any measure".

ICANN could also be hit with litigation from businesses that failed to win approval for their proposals after paying a $50,000 application fee. Over 200 proposals were submitted by 44 applicants, but the board voted to add just seven new domains - aero, .biz, .coop, .info, .museum, .name and .pro - to the existing ones.

ICANN's decision to limit the number of new domains has won praise from some observers. Mark Heltzer, government relations manager at the International Trademark Association in New York, said: "If you're going to introduce new domains, introduce them responsibly so there isn't a wholesale ripping off of intellectual property."

Business interests Others believe the approach taken by ICANN was unfair. Mikki Barry, president of the Domain Name Rights Coalition, said: "It's pretty obvious that more top-level domains means more opportunity for small businesses and entrepreneurs to get meaningful domain names that reflect their business interests as well as their free speech interests."

Esther Dyson, who recently stepped down as ICANN's chairman, said she would have liked to have added more domains.

Dyson has claimed that ICANN wants to keep the process to a manageable size for technical reasons, primarily to avoid overloading the servers that translate domain names into actual IP addresses. She said: "You want to avoid unnecessary technical challenges to a system that seems a little stressed currently."

Dyson defended ICANN's decision as "reasonable" under the circumstances. She said the organization "is supposed to recognize consensus rather than act on its own whims". "While quite a few people want a large or even unlimited number of new TLDs, another large group wants no new ones or a limited number. So we took the conservative route in the middle."