Cheap registration of domain names is driving the growth in spamming according to research from McAfee.

A study commissioned by the company showed that many security problems stem from the way that some websites are registered,. In particularl, the study showed that too many owners of spamming sites can, after they're blocked, change websites to continue their scams.

McAfee analysed 8.1 million of the world's most trafficked websites registered on 265 top-level domains (TLDs), such as ".com" and ".biz" along with country-specific ones, such as ".jp" for Japan.

McAfee offers a free tool, SiteAdvisor, that determines if websites send spam, host bad programs or have excessive pop-ups. McAfee, which bought SiteAdvisor in April 2006, also offers a pay version with more advanced features.

Small islands with their own TLDs remain troublesome. For example, some 18.5 percent of websites registered under the ".st" TLD are considered "risky" for either spam or other malicious activity, McAfee said. The TLD belongs to Sao Tome and Principe, a country of two volcanic islands west of Gabon.

Tokelau (.tk), a territory of New Zealand in the south Pacific, and Niue (.nu), also in the south Pacific east of Tonga, give out domains for free. That's good for scammers, who often need to register new domains as older ones are blocked by security software.

Niue also allows anonymous registration of websites. Nine years ago the country declared "no tolerance" policy against spammers, but McAfee said it wasn't a deterrent.

The safest TLDs belong to countries with stronger registration rules. Japan, Ireland, Sweden and Finland require a local postal address, while businesses in Norway have to register with the government to get a ".no" domain. Consequently, McAfee found the lowest percentage of bad websites in those domains.

Australia and Canada, McAfee said, require a local contact for registration, which often deters spammer since registrations take more time.

The ".info" domain ranked first among generic TLDs for its percentage of risky sites, at 7.5 percent, McAfee said. The domain also hosts many sites that send "spammy" e-mail, the vendor said.

SiteAdvisor submits an e-mail address to websites and counts how many e-mails are received. Users have a 73.2 percent chance of receiving a spam e-mail by giving their address to a random ".info" site, McAfee said.

The ".com" domain - created in the 1980s - came in second for risk, with 5.5 percent of its websites considered questionable, McAfee said.