There is no doubt that Wikipedia is the world’s largest encyclopedia which contains millions of rare articles and information that can not be found anywhere. Wikipedia has made clear many times that it’s a well-funded non-profitable organization and it doesn’t display any kind of advertisement in its pages except the notification regarding the fund raising events. But there are reports that some Wikipedia pages are displaying advertisements of some profitable companies. If you find the same, then most probably your computer is infected with malware and needs to be paid attention.
There may be several reasons for this but most important reason is that your Internet Service Provider (ISP) is feeding advertisement into the web pages. Another reason may be that the malware get access in your browser through installed extensions. These extension-induced ads could either be present only on Wikipedia or in every site that you visit. For instance, an extension “I want this” installed in chrome browser can inject malware.
To remove it, open the options menu via the “Pipe-Wrench” icon on the top right, and choose Settings. Next, open the Extensions panel and there is the list of extensions installed. Now remove that Extension by clicking the Remove button next to an item.
Once again I want to highlight and re-inform readers that Wikipedia still doesn’t display ads anywhere. In case, you are viewing them, it’s time to take action against them.