Even the 'acceptable' adverts (plain text ad's) can end up linking to pretty some dodgy software.
Not so long ago I stupidly hit the download button on an advert instead of for the software I actually wanted. I ended up blindly installing some sketchy application. OK this is my own fault, I should be savvy enough to spot this. I imagine that this trick hooks the generally population on a regular basis.
Another modern classic I see is content with numbered pages, where the user must click next to continue reading, and adverts that look like large next buttons.
It's unfortunate that this is the case and I don't know what the solution is that will allow companies to have a decent revenue stream whilst protecting their users.
Adblock detection is pretty effective so blocking users is one option.
Maybe if an advertiser started to produce higher quality results then they'd gain some trust. Too many bad eggs currently, and no incentive for me to participate.