NEW YORK, May 10 (Reuters) - A group of California Internet users have sued Facebook for using its "Like" button to track their online activity.
The class-action lawsuit, filed in Santa Clara Superior Court on Monday, accused Facebook of placing its "Like" button on third-party websites to collect users' browsing information, even if the users don't click on the button and even if they are not Facebook members.
Facebook's "Like" button, a thumbs-up symbol that allows Facebook members to share links, is the latest target in a wave of privacy lawsuits filed against technology companies over the collection of user data.
The suit accused Facebook of using the "Like" button to plant tracking cookies on the computers of both members and non-members of Facebook. Each time a user visits a site with a "Like" button, the user's updated browsing history is relayed to a Facebook server and associated with a unique identification number, according to the complaint. That data is then "priced, bought and sold in discrete units for marketing and other purposes," the suit said.
Websites have an incentive to add "Like" buttons to their pages to increase traffic and drive advertising revenue, according to the lawsuit, which described the feature as an "indelible part" of the online experience. The suit said over 2.5 million websites have integrated the "Like" button, with 10,000 more adding it every day.
Facebook spokesman Andrew Noyes said the lawsuit was "completely without merit" and that the company would vigorously fight the claims.
Peter Seidman, a lawyer with Milberg representing the plaintiffs, said the firm first learned of Facebook's "Like" button tracking tool from an academic paper by Arnold Roosendaal called "Facebook Tracks and Traces Everyone: Like This!" The study reported that Facebook was using "Like" buttons to trace the activity of website visitors, expanding its reach "far beyond (its) own platform and members."
Roosendaal, a doctoral candidate at Tilburg Law School in the Netherlands, said he noticed while surfing the Web that pages with "Like" buttons were leaving a unique cookie on his computer. He said his findings have prompted German data protection officials to investigate Facebook for accessing and storing the personal data of non-members. Roosendaal said Facebook acknowledged his paper's findings but claimed the tracking was the inadvertent result of a computer bug that has since been fixed. But Roosendaal said that sites with the "Like" button have left a cookie on his computer as recently as last month.
The California lawsuit claims that the alleged tracking is still ongoing, according to Seidman.
Milberg, the firm representing the plaintiffs, has filed numerous privacy lawsuits against Apple, MySpace, Sony and LinkedIn over the alleged collection and leaking of users' personal information. California is a popular venue for the privacy suits because many of the technology companies are there and because it is one of the few states to provide a constitutional right to privacy, Seidman said.
A "do-not-track" bill (SB 761) currently making its way through the California legislature would give consumers the legal right to bar companies from tracking their online behavior. Last month, numerous companies, including Facebook and Google, sent an opposition letter to the bill's sponsor, state senator Alan Lowenthal, calling it an unconstitutional burden on Internet commerce and an act of blatant discrimination against the advertising industry.
The case is Ung et al v. Facebook Inc, Santa Clara Superior Court, No. 111-cv-200467.
For Ung et al: Jeff Westerman, David Azar and Peter Seidman of Milberg.
For Facebook: Not immediately available.
(Reporting by Terry Baynes)