Power.com, a San Francisco based aggregator of social networking sites, on Friday sued Facebook in a California court to try to resolve who owns data on social networking websites - users or the sites. Power says users do. It plans to take a stand in its lawsuit to ensure that users have rights to "complete and total" ownership and control of their content, and to protect their content from other users and corporate entities.

The countersuit accusing Facebook of unfair competition, restraint of trade and creating a monopoly, comes about six months after Facebook sued Power.com for alleged copyright and trademark infringement, unlawful competition and fraud. Power denied those allegations in its counterclaim, and asked that Facebook be permanently barred from "anti-competitive practices." It also requested unspecified damages and costs. Facebook said in a statement that it made "numerous attempts" to work with Power before suing the company, "but ... they continued to put Facebook user data at risk." The claims in Power's lawsuit are "without merit, and we will fight them aggressively," the statement said. Power allows users to access multiple social networking accounts through a single portal and to manipulate features and data on those accounts. In its cross complaint, Power says it "believes in a borderless Internet where users have the right to control their own data." Facebook, which in its lawsuit says it "tightly" controls access to its network, earlier this year had to back off what appeared to users to be an attempt to take ownership of data posted on the site through a change in its terms of service. Power Chief Executive Officer Steve Vachani says Facebook is stifling competition by restricting consumers' access to their data, echoing a similar controversy that plagued the mobile phone industry. "If you block users' data or any tools they would like to use to get that data ... this is similar to phone companies that blocked you from moving your phone number," Vachani said. "Users have built huge amounts of time with (Facebook)... and they lock up your information."

Facebook had similar complaints against contact management web site Plaxo, which later integrated its aggregating tools on Facebook Connect, where software developers can post approved self-service tools for Facebook users. Power rejected the chance to post its tools on Facebook Connect, saying in its cross complaint that it could not meet Facebook's deadlines for doing so. Power has 8 million members and aggregates Twitter, MySpace, LinkIn, HI5 and Okut. Facebook has 200 million active users. Power.com's answer and countersuit is Facebook Inc vs. Power Ventures Inc, Case No. 5:08-05780, U.S. District Court for the Northern District of California.