“We never run ads on Wikipedia. Wikipedia is funded by more than a million donors, who give an average donation of less than 30 dollars. We run fundraising appeals, usually at the end of the year. If you’re seeing advertisements for a for-profit industry (see screenshot below for an example) or anything but our fundraiser, then your web browser has likely been infected with malware.”
For example that we have seen installs itself as a browser extension. The extension is called “I want this” and installs itself in Google Chrome. To remove it:
Open the options menu via the “pipe-wrench” icon on the top right, and choose Settings.
Open the Extensions panel and there is the list of extensions installed.
Remove an Extension by clicking the Remove button next to an item.
There is likely other similar malware that injects ads into Chrome, Firefox, Internet Explorer and other popular browsers. If you see examples that you can document, please point them out in the comments.
Ads injected in this manner may be confined to some sites, even just to Wikipedia, or they may show up on all sites you visit. Browsing through a secure (HTTPS) connection (which you can automate using the HTTPS everywhere extension) may cause the ads to disappear, but will not fix the underlying problem.
Disabling browser add-ins is a good starting point to determine the source of these types of ads. This does not necessarily fix the source of the problem either, as malware may make deep changes to your operating system.
Internet users are advised to install at least a basic antivirus solution to protect them from potential threats. In some situations, these advertisements aren’t designed only to earn money for the spammers, but they can also serve Trojans and other nasty elements.
Whichever the case may be, Wikipedia assures its customers that advertisements will never be displayed on the site. For more information please go on wikimedia foundation