How prevalent is the use of tracking cookies that get planted on your computer after browsing a website so it can keep track of what you're doing? Turns out that not only do the major websites like to plant their own tracking cookies on you, they're also happy to stick a lot of third-party cookies on you, too.Does two-factor authentication need to be fixed?According to Keynote Systems, an analysis it did of online behavioral tracking on 269 top websites across four industries -- "news & media," "financial services," "travel & hospitality," and "retail," -- showed that 86% of the sites place one or more third-party tracking cookies on their visitors.Keynote Systems, whose long-time services include performance-monitoring of websites, also says its study shows that 60% of these third-parties had at least one tracker that didn't promise to comply with at least one common tracking standard. Keynote says that of the 211 third-party trackers it identified, "only one committed to honor a visitor's request not to be tracked via the new 'Do Not Track' feature." This gives consumers a way to opt out if being tracked. Keynote says it also checked to figure out if there was a "promise to anonymize data."Keynote found that nearly all the websites in the "travel & hospitality" and "news & media" categories have third-party tracking. The "news & media" sites are said to "expose site visitors to an average 14 unique third-party tracking companies during the course of a typical visit." Keynote also adds that it was also "surprising" that three out of four websites in the "financial services" category also "expose visitors to third-party tracking."Keynote Systems says the tracking phenomenon is all about advertising and revenues that websites can pull in."Behavioral advertising, a common use of third-party tracking data, is an increasingly common practice on the Web and one of the primary ways websites fund their operations. Third-party trackers place cookies on the browsers of site's visitors to track a user's clicks and path through the Web. They can also make note of things like what the visitor buys and where the visitor goes once they leave."Ray Everett, Keynote's director of privacy services, says it all reflects a "'wild West' mentality" and that "aggressive tracking companies" could be placing website publishers in a difficult position and even exposing them to legal risk. But he points out the "burden of policing third-party trackers falls squarely on the shoulders of website publishers" because they are clearly responsible for their content and brand reputation.Ellen Messmer is senior editor at Network World, an IDG publication and website, where she covers news and technology trends related to information security.Read more about wide area network in Network World's Wide Area Network section.