U.S. lawmakers, considering legislation aimed at protecting consumers’ online privacy, said the market for smartphone applications needs to be regulated to prevent the inappropriate sharing of user data.

As mobile devices “become more powerful, more personal information is being concentrated in one place,” Senator Jay Rockefeller, a West Virginia Democrat, said today during a Senate Commerce Committee panel hearing in Washington on mobile privacy. “These devices are not really phones — they are miniature computers.”

“The mobile marketplace is so new and technology is moving so quickly that many consumers do not understand the privacy implications of their actions,” Rockefeller, who chairs the Senate Commerce Committee, said in prepared remarks released before the subcommittee hearing.

Apple Inc., Google Inc. and Facebook Inc. are facing increasing scrutiny from Congress over how they collect, use and store customer information, including data gathered from smartphones and other wireless devices. Executives from the three companies are scheduled to testify today.

In prepared testimony released today, Google defended its handling of user data tied to mobile devices using Android software, telling U.S. lawmakers that the company seeks consent for the collection and use of location information.

“Google is also very careful about how we use and store the data that is generated by these services,” Alan Davidson, the Mountain View, California-based company’s director of public policy, said in the testimony. “The location information sent to Google servers when users opt in to location services on Android is anonymized and stored in the aggregate. It’s not tied or traceable to a specific user.”

Protect Children

Davidson said the company also provides parental controls to protect children, according to the testimony.

Facebook Chief Technology Officer Bret Taylor will tell lawmakers that his company has “robust privacy protections,” according to his prepared testimony.

Taylor said that mobile technology “will play an increasingly important role” in how people use Facebook, the world’s largest social networking site, according to the testimony. The Palo Alto, California-based company is “testing a new policy that communicates about privacy in a simple, interactive way,” he said.

Facebook requires developers of applications and websites that connect to its service to be “responsible stewards” of user information, according to the testimony.

Catherine Novelli, vice president of worldwide government affairs for Cupertino, California-based Apple, is also on the witness list.

FTC Role

Rockefeller, who introduced legislation May 9 that would let consumers choose not to have their online activities tracked, said the Federal Trade Commission wasn’t being “aggressive” enough on Internet privacy.

He pressed David Vladeck, director of the FTC’s bureau of consumer protection, on whether the agency is making sure that mobile applications comply with laws governing children’s online privacy.

Vladeck said the FTC “has a number of investigations ongoing in the mobile space, including apps aimed at children.”

“We are looking for good enforcement targets in this space,” Vladeck said.

Rockefeller said yesterday that he sent letters to Apple and Google asking them whether applications that run on their mobile platforms comply with online privacy laws for children.