Country-code domains, derived from a list kept by the International Organization for Standardization, typically disappear when a country ceases to exist or changes its name. Both Yugoslavia and Czechoslovakia lost their domain names after they broke up into smaller nations. So did Zaire after it became the Democratic Republic of Congo.

The Internet's key oversight agency, the Marina del Rey, Calif.-based Internet Corporation for Assigned Names and Numbers, and its predecessors have made several efforts since the 1990s to eliminate the ".su" address.

All have failed.

In late 2006, ICANN even sought advice from the community on how best to revoke outdated suffixes. Yet the resistance continued, and the phase-out seems to be in a stalemate. The domain continues to work normally but is listed in records as "being phased out."

"There are no technical issues," said John Crain, ICANN's chief technical officer. "It all comes down to politics."

The ".su" domain dates back to September 1990, a little more than a year before the Soviet collapse. Russia was given the ".ru" domain name in 1994. Other former Soviet republics were also assigned codes.

But the owners of ".su" sites stubbornly resisted switching on commercial, political and patriotic grounds. Some even accused the White House of scheming to eliminate the last remnants of its Cold War rival.

As a compromise, the Russian organization responsible for registering new domain names under ".su" agreed to stop issuing new ones, while existing ".su" addresses were allowed to continue for the time being.

A loophole allowed existing ".su" addresses like "lenin.su" to assign subdomains such as "vladimir.lenin.su." As a result, the online population at ".su" kept growing throughout the 1990s. Then, in 2001, in response to pressure from users eager for freer access, registration in ".su" was opened to everyone everywhere.

The price was kept artificially high — $120 per name, six times the price for ".ru" — to limit the number of new users and prevent entrepreneurs from grabbing names for resale in a practice called cybersquatting, said Andrey Vorobyev, spokesman for RU-Center, the body authorized to register domain names.

But in January, RU-Center dropped the price for ".su" to $25 in a bid to boost the domain's worldwide popularity.

The attractive new price sparked a registration rush that bumped up the number of ".su" sites to 45,000 today, more than quadruple the 11,000 registered as of late 2006. The demand shows no signs of relenting — the jump from 31,000 in January represents a 45 percent rise.

But by domain name standards, the number of ".su" registrations is still very small. Russia's ".ru," for instance, has more than 1 million names. Germany's ".de" has 12 million, and the global ".com" has about 75 million.

Champions of the online Soviet domain say there is still plenty of room for growth.

Some envisage the ".su" domain as a virtual venue for those who fondly recall the old Soviet Union as a place where Russian, the lingua franca of the Soviet empire, knit together a host of Asian and European ethnic groups and cultures.

And by late April, the ".su" domain plans to start allowing names in Russian; currently such names are limited to English letters, numerals and the hyphen.