it has happened to me couple of times today already on sites like http://www.businessinsider.com. I start reading a blog post and suddenly those damn javascript-css-popup ads comes bloging the screen.<p>How many of you continue reading a post after popup ad ? Are you skipping already some blogs because those ads (like I'm trying to)?
I would say 1/3 times I will just close, instead of clicking through. I would say in video it's different though, I will often sit through many ads, even ones that are clickable (e.g. hulu), because the content is more passive.
When I see a pop up on an article, I generally close immediately. It is pretty clear that they are simply trying to monetize my visit, and whatever content is there is just more bait for that. I will put up with banner ads to some extent, but as a general rule if there are more ads than I feel like there need to be, or if the content of the article is broken into different 'parts', I'll just close on general principle.
I generally just close an article instantly if it has one of those panels obscuring the text. There's enough other interesting stuff to read on the web that I'm not willing to put up with manipulation like that.