Most likely the ads are coming form an extension or add-on from one of your browsers. I recently thought that my hosting company starting placing ads on my business account, I was slightly pissed, cause I was like, why am I paying for a business account and getting ads?
In my case, the person or group who created the chrome extension, clearly stated that future updates may contain ads, but until recently they had never implemented it. Soon as they did, I removed the extension.
I also had adblock as well, the ads went past that since they were being generated by the Pintrest extension. BTW, the Pintrest extension was not the “official” release.