Not only do you get unwanted ads or worse, redirected to malware websites, but the extension can be rewritten to send phishing ads in your name to your contact lists.
It’s still beyond me why people moved away from Firefox over some very vocal homosexuals pushing out a right-of-center CEO and moved towards Google’s Chrome browser which is basically an intelligence gathering platform.
Chrome is a virus, IMO. They glitz it up with “cool features” and promote extension/add-on development for “privacy” tools, but we all know what’s really going on.
As a test, I took a PC with Windows 7, installed Chrome, and I put the machine behind a proxy that logged all of the traffic. (this could also be accomplished through netstat, but I had a proxy server available which makes it easier.) Chrome had 40% more established connections to Google (straight out of the box, no extensions or add-ons) than Firefox did. Further, many of the IPs were not configured with reverse lookups, meaning Google either intentionally obfuscated the endpoints or they were negligent in configuring their DNS. (A traceroute revealed the traffic going through Google’s infrastructure portals but timed out thereafter.)
I don’t trust Google. I don’t want to do business with them. I intentionally block all of their infrastructure tools on my personal machines. And I will advocate against them until I’m blue in the face. I don’t believe they have anyone’s interests at heart except their own.