Beacon (noun): That which gives notice of danger

It is becoming increasingly apt that Facebook named their new Web tracking advertising service “Beacon.”

As I briefly mentioned here, Facebook now has admitted, contrary to earlier assurances, that their Beacon ad system tracks users’ off-Facebook activities even if those users are logged off from the social-networking site and have previously declined having their activities on specific external sites broadcast to their Facebook friend.

Now we learn that Beacon’s reach extends beyond Facebook users:

If you think that just because you have never signed up for Facebook you’re immune to the tracking and collecting of user activities outside of this popular social networking site, think again.

Facebook’s controversial Beacon ad system tracks activities from all users in its third-party partner sites, including from people who have never signed up with Facebook or who have deactivated their accounts, CA has found.

Beacon captures detailed data on what users do on these external partner sites and sends it back to Facebook along with users’ IP addresses, Stefan Berteau, senior research engineer at CA’s Threat Research Group, said Monday in an interview.

This happens even if users delete the Facebook cookie. “The Facebook Javascript is still called by the affiliate site and the information is passed in,” he said. In the case of users without accounts or with deactivated accounts, the data isn’t tied to a Facebook ID, he said.

However, it is well-known that IP addresses provide a variety of information about users, and have in some cases been used to identify individuals.

The information captured by Beacon in these cases includes the addresses of Web pages visited by the user and a string with the action taken in the partner site, Berteau said.

Dan Solove correctly sums up the situation: Facebook is the new DoubleClick.

Dan also notes that it takes two to tango, and that the tracking made possible by Facebook's Beacon necessitates the cooperation of various online partners. Consumerist has the whole list, which includes:

• AllPosters.com
• Blockbuster
• CBS Interactive (CBSSports.com & Dotspotter)
• Citysearch
• CollegeHumor
• Hotwire
• Joost
• LiveJournal
• National Basketball Association
• NYTimes.com
• Overstock.com
• (RED)
• Sony Online Entertainment LLC
• Sony Pictures
• STA Travel
• The Knot
• TripAdvisor
• Travelocity
• TypePad
• WeddingChannel.com
• Zappos.com

Remember: a beacon warns you of impending danger. If you plan to use a website partnering with Facebook's Beacon, steer clear to avoid the hazard.