Google has removed two extensions from the Chrome Web Store for violating the search giant’s terms of service. Specifically, the extensions – “Add to Feedly” and “Tweet This Page” – both included code that were used to serve advertisements according to a report from the Wall Street Journal.

Multiple Chrome users took to message boards over the weekend to voice their concerns despite the fact that each extension had fewer than 100,000 users. As the Journal highlights, one user classified Add to Feedly as spam that would cause ads to suddenly pop up on any website visited.

Independent reports from two different websites outline how the extensions got on Google’s bad side. In both cases, the developers sold the extensions to another party that then silently updated them to include the offending code.

This was allowed initially simply because Google does not review changes to an extension’s code after it has initially been approved for inclusion in the Chrome Web Store. And since there are no change logs, the source of the unwanted advertisements can be difficult for end users to track down.

If you recall, Google implemented an update to its Chrome Web Store policy last month that called for extensions to have a single purpose that is narrow and easy to understand. The company at the time found that a number of extensions were crowding the browser user interface and slowing down the browsing experience.