Seemingly, some users are seeing commercial ads on Wikipedia. A May 14 blog post
by Philippe Beaudette, Director of Community Advocacy, affirmed that users should not see any sort of advertisement on the site.
"If you’re seeing advertisements for a for-profit industry or anything but our fundraiser, then your web browser has likely been infected with malware," Beaudette's post said.
An example cited by Wikipedia is a malware that installs itself as a Google Chrome browser extension called "I want this." The company warns that similar malware can occur in Firefox, Internet Explorer and other browsers, and it can "target multiple websites at once," reported PC World
Additionally, this type of malware can redirect users to websites or give search results that users were not seeking, said security company Sophos'
"Disabling browser add-ins is a good starting point to determine the source of these types of ads," Wikipedia said. "This does not necessarily fix the source of the problem either, as malware may make deep changes to your operating system."
Wikipedia also noted that browsing through a secure (HTTPS) connection can remove the ads from view, but warns this also won't fix the underlying cause of why the ads are appearing.
Users are advised by security experts to install (if not already installed) up-to-date anti-virus software and routinely run it to eliminate any possible underlying rogue programs. While ads may be one problem, harmful malware can also be causing malicious damage in the background.
Malware can come in many forms, including worms, viruses, trojan horses and spyware. Some forms of malware are more harmful than others. Depending on the type of malware written, an infection can lead to deleted or corrupted computer files, or, in some cases, render a system unusable. There are forms of malware that steal information, leading to identity or financial theft.
Although, Wikipedia did indicate individuals using free wireless in public spaces or Internet café's may also see ads on its pages, and points to a New York Times
piece. In this scenario, ads are inserted by Internet providers, but definitely not placed by Wikipedia.