Over 190 Chrome extensions were killed by Google as the company ruled them to be nothing more than malware. The ad injecting extensions did not provide enough value over the issues they presented to users by showing ads or installing additional software. The University of California Berkley was involved in the study that led to the malware designation for the add-on products. 194 different extensions were removed from the popular browser and measures were put into place to prevent new ones from performing similar activities against users.
Google requires that ad-injecting behavior be disclosed in the extension gallery but they do not ban the extensions outright. Superfish spurred Google to take harsher measures against extension writers after Lenovo computers were found to be injecting ads into search results. In addition, the Superfish bug could place ads into secure internet activity, thus making the transmission un-secure. Lenovo has been working with Microsoft to remove the Superfish software from computers.
How To Remove Malware and Adware Chrome Extensions