The Internet's key oversight agency relaxed rules Thursday to permit the introduction of hundreds, perhaps thousands, of new Internet domain names to join ".com," making the first sweeping changes in the network's 25-year-old address system.

The Internet Corporation for Assigned Names and Numbers unanimously approved the new guidelines as weeklong meetings in Paris concluded.

ICANN also voted unanimously to open public comment on a separate proposal to permit addresses entirely in non-English languages for the first time.

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New names won't start appearing until at least next year, and ICANN won't be deciding on specific ones quite yet.

The organization still must work out many details, including fees for obtaining new names, expected to exceed $100,000 apiece to help ICANN cover up to $20 million in costs.

Domain names help computers find Web sites and route e-mail. Adding new suffixes can make it easier for Web sites to promote easy-to-remember names — given that many of the best ones have been claimed already under ".com."

New names could cover locations such as ".nyc" and ".berlin" or industries such as ".bank." The hefty application fees could curb a rush for individual vanity names, though larger companies might claim brands like ".disney."

The new guidelines would make it easier for companies and groups to propose new suffixes. ICANN had accepted bids in 2000 and 2004, but reviews took much time, and one — ".post" for postal services — remains pending more than four years later.

Ultimately, only 13 have been approved in those two rounds.

The streamlined guidelines call for applicants to go through an initial review phase, during which anyone may raise an objection on such grounds as racism, trademark conflicts and similarity to an existing suffix. If no objection is raised, approval would come quickly.

Some ICANN board members expressed concerns that the guidelines could turn the organization into a censorship regime, deciding what could be objectionable to someone, somewhere in the world.

"If this is broadly implemented, this recommendation would allow for any government to effectively veto a string that makes it uncomfortable," said Susan Crawford, a Yale law professor on the board. She voted in favor of the rule changes, but called for more clarity later.

None of the new names is likely to dethrone ".com" as the world's leader, and critics fear new suffixes will merely force companies and organizations to spend more money registering names such as "microsoft.paris" simply so others can't.

The other proposal before ICANN would permit addresses entirely in non-English characters for the first time. Specific countries would be put on a "fast track" to receive the equivalent of their two-letter country code, such as Bulgaria's ".bg," in a native language.

The ICANN board said it would seek public comment on the guidelines before its next major meeting in November.

Demand for such names has been increasing around the world as Internet usage expands to people who cannot speak English or easily type English characters.

Addresses partly in foreign languages are sometimes possible today, but the suffix has been limited to 37 characters: a-z, 0-9 and the hyphen.

In other action, ICANN approved recommendations designed to clamp down on domain name tasting — the online equivalent of buying new clothes on a charge card only to return them for a full refund after wearing them to a big party.

A loophole in registration policies now allows entrepreneurs to grab domain names risk-free for up to five days to see whether they generate enough traffic and advertising dollars.

That practice ties up millions of Internet addresses, making it even more difficult for individuals and businesses to find good names in the crowded ".com" space.

The new guidelines would withhold refunds if too many are returned.