The company’s approval as an internet domain name registrar last week has prompted much speculation as to how it intends to leverage the new accreditation.

One intriguing possibility put forward by a source claiming knowledge of Google’s plans is that access to domain registries will be needed for a system that would help purge spam and poor quality links from its search index.

Such a system would prevent domain speculators and search spammers from capitalizing on traffic inherited from the previous owners of defunct web sites.

If implemented, the move could reduce the number of advertising clicks Google gets from such sites, and could push up the overall pay-per-click fee over the longer term.

As we reported yesterday, Google has become an ICANN-accredited domain name registrar, giving it access to sell .com, .info and .net names, among others.

While this would allow the company to become a registrar, and help with entering the web hosting market, the firm said it has no current plans to do so.

For a company of Google’s resources, it could afford the measly $10,000 accreditation for many reasons. AOL and Amazon.com are also accredited, but do not sell domains.

Google said in a statement sent to reporters: Google has become a domain name registrar to learn more about the internet’s domain name system… we believe this information can help us increase the quality of our search results.

One idea put forth is that Google intends to use its new capability to help more accurately index second-hand domains that exploit the ranking of the previous owner’s site.

Currently, one of the ways people can quickly build up traffic to their sites is to register a domain name that somebody else has previously used but has allowed to expire.

A web address that already has in-bound links, listings in directories, and high placement in search engines (Google calls this PageRank), is far more valuable than a new domain.

There are a lot of big domain name buyers, and some of the data they look at is the Google ranking, the Yahoo ranking, and the Alexa ranking, said Taryn Naidu, president of expiring domain auction service Pool.com Inc.

Very often, speculators re-register these domains and set them up to point to a page that contains nothing more than advertising links, which generate revenue when surfers click on them.

For surfers, this increasingly means that they may follow an out-of-date link that leads to a content-free page of advertising, rather than the page they expected.

Because search engines including Google count the number of links leading to a site as part of their ranking process, speculators can inherit the ranking of the domain’s previous owner, increasing traffic.

Becoming an ICANN registrar means that Google will be able to negotiate access to the so-called batch pool of expiring .com and .net domains, operated by VeriSign Inc.

This pool is mainly used by companies that specialize in giving speculators early access to dropping names, in the periodic add storm scramble to register cool expiring domains.

But Google, the theory goes, would be able to use it to see which names actually do drop and a re-registered. It would then be able to reset the PageRank for that domain, meaning the new registrant would have to start marketing the site from a clean slate.

Many of these sites get their advertising links from Google AdSense or Yahoo! Overture. Yahoo or Google give the site owner a percentage of each revenue-generating click.

So if Google is in fact planning on making a move that could reduce the traffic these sites get, it could have a knock-on impact on how many advertising clicks are generated.

But it could also improve the quality of the clicks, minimizing the amount of random drive-by traffic advertisers get, which in turn increases the price advertisers are willing to pay for each click they get.

That’s a key problem for Google, according to its competitors. Rival Kanoodle Inc, for example, told ComputerWire recently that it demands a much higher price-per-click by vetting the content providers that display its clients advertising.

Google, which did not return calls for comment, yesterday highlighted improving the quality of its targeted advertising as something that will drive revenue growth.

The firm reported fourth-quarter net income that was up to $204m from $27m a year earlier, on revenue that almost doubled to $1bn.

Despite committing to improve the quality of the clicks it delivers advertisers, the company does offer its own domain parking service already.

AdSense for Domains offers to park unused domains for customers, putting a Google search page and advertising in place of an otherwise blank page.

Rather than a scattershot approach, Google claims the links it displays at each parked domain are contextually linked to the text of the domain itself.