The most popular extension, and the 2nd most popular, just like the 6th, 7th, 9th and 10th most popular, are ad-blockers. I guess it's only marketers that love targeted ads...
That maybe, but it might be hypocritical if you're working at a private business that generates sales via ads, which in effect pay your salary. I'm not against ads, so I wouldn't use an ad-blocker on principle, I would just avoid visiting sites that show excessive ads.