Browsers extensions are great as they enhance the usability and your experience with your browser. However, there are some extensions out there that will actually do the opposite. This seems to be a bigger problem for Chrome but there are a couple known ‘spying’ extensions in Firefox. These ‘evil’ extensions may track you or as in the case with Scott Hanselman inject ads into sites you are viewing.
I wanted to download a YouTube video recently so I installed a “U-Tube Downloader” extension. It is highly rated, seemed legit, so I added it. It puts a nice Download button next to any YouTube video. Like greasemonkey script it was there when I needed and it, and out of sight otherwise.
I installed it and forgot about it. So, put a pin in that and read on…
Here is a list of “known” tracking extensions for Firefox and Chrome. Do note that this list was from January of 2014, so there are likely many more that are not on this list.