If you see an advertisement on Wikipedia, there's a good chance you have malware on your computer.
That's the official statement from Wikipedia, which warned its millions of visitors yesterday (May 14) that if they come across ads for anything except Wikipedia's own fundraising appeal, which occurs at the end of the year, it's a sign their Web browser could be infected with harmful software.
"We never run ads on Wikipedia," the online encyclopedia said in its statement. "If you're seeing advertisements for a for-profit industry … then your Web browser has likely been infected with malware."
[13 Percent of Homes With Broadband Infected With Malware]
Wikipedia showed a screenshot of an example, in which malware triggered the site to display a banner ad for a T-shirt company. These ads are often caused by Web browser add-ins and extensions, including one called "I want this," for Google Chrome. The companies are legitimate, but their ads have no place on the site.
To safeguard your browser, Wikipedia suggests you browse using a secure, encrypted HTTPS connection, disable browser add-ins, and run anti-spyware and anti-virus software on your computer.