James Martin/CNET

Facebook is getting more heat over two controversial practices--tracking users after they log out and new automatic "frictionless sharing."

The tracking, done with cookies on users' computers, has prompted criticism from lawmakers and now a lawsuit, while privacy groups and regulators in Ireland are concerned about a new sharing feature that automatically posts user activities to news feeds without users intentionally doing so.

A blogger wrote last weekend that he discovered that his Web surfing was being tracked by Facebook even after he logged out. Facebook admitted that it personalizes content by putting cookie files on user computers that remain even when users are logged out, but told CNET earlier this week that it quickly acted to remove uniquely identifying data from post-logout cookies and that it did not store or use that cookie data for tracking.

"This admission came only after an Australian technology blogger exposed Facebook's practice of monitoring members who have logged out, although he brought the problems to the defendant's attention a year ago," according to the complaint filed in federal court in San Jose, Calif., and reported on by Bloomberg today.

The lawsuit was filed by Perrin Aikens Davis of Illinois and it seeks class-action status. It seeks unspecified damages and ask the court to block the tracking based on alleged violations of federal wiretapping, computer fraud, and abuse laws, according to the report.

"We believe this complaint is without merit and we will fight it vigorously," Facebook spokesman Andrew Noyes told CNET in an e-mailed statement.

Also today, the Irish data protection commissioner plans to investigate Facebook's privacy-related activities following complaints by privacy groups in Europe and the U.S., according to a Reuters report.

It's been a rough week for the company. Yesterday, a collection of advocacy groups asked the Federal Trade Commission to ban Facebook's "frictionless sharing" and new Timeline features announced at F8 last week. On Wednesday, two U.S. congressmen asked the FTC to investigate Facebook over the post logout cookies. And a Chicago company has filed a trademark infringement lawsuit against Facebook over the Timeline feature.