I noticed this same thing when viewing YouTube on my daughter's laptop. Oddly spammy ads where there normally were no ads.
I guess the new model for adware/malware is to try to integrate so seamlessly that a normal person doesn't even realize they are seeing someone else's ads.
Doesn't this sort of parallel real-world infections? Something too obviously virulent in real life will kill the host before it gets to reproduce; so it makes sense to be as innocuous as possible while still reproducing/bringing profit.
I guess the new model for adware/malware is to try to integrate so seamlessly that a normal person doesn't even realize they are seeing someone else's ads.