When I watched Youtube a new browser window popped up with a site called flashtalking opt-out. I closed the window without clicking anything on the page in case of malicious links. Then it popped a day later or two. I don't remember what I was doing, but I wasn't watching Youtube that time. I did not click anything that time either. I also searched my computer on startup and did a full search using Avast, and also Windows Defender, they did not find anything. As well as removing all cookies in chrome from the last 4 weeks. It hasn't happened again yet.

I haven't done anything unusual and haven't installed anything. I read another post on another subreddit that had the same problem just days ago.

Has someone had the same thing happen or does someone know what it is and why it pops up on regular, nonmalicious sites? Should I be nervous? Is it a virus?