Domain registrar and Web hosting provider Network Solutions is reportedly using its customers’ sub-domains to run ad-generating links, according to The Register.

Earlier this week, Network Solutions customer, Win Betteridge, told TechCrunch that the Web host uses the sub-domains of customers’ websites for “parking” pages. He said he was suprised when he discovered that the sub-domains of his “social gaming” site, GotGame.com, resolved to ad-infested parking pages.

“For instance, app.gotgame.com resolves to a Network Solutions page with text links, including ‘Poker Tournaments’ and ‘Texas Holdem Games,’” Betteridge told The Register.

Apparently, Network Solutions reserves the right to do this with all the websites it hosts and even includes this clause in its terms of service, which reads:

“You also agree that any domain name directory, sub-directory, file name or path (e.g.) that does not resolve to an active Web page on your website being hosted by Network Solutions, may be used by Network Solutions to place a “parking” page, “under construction” page, or other temporary page that may include promotions and advertisements for, and links to, Network Solutions’ website, Network Solutions product and service offerings, third-party websites, third-party product and service offerings, and/or Internet search engines. You agree that Network Solutions may change the content and/or appearance of, or disable any of these temporary pages at any time, in its sole discretion, and without prior notice.”

Customers can opt out of this practice if they wish, however, they would need to know that it existed in the first place. Given the considerable length of the terms of service page, it seems improbable that customers would know about such a practice. And while other Web hosts may follow a similar practice, it is not exactly right.