As I mentioned earlier, I did have a router get hacked a week or so ago that simultaneously put all these kinds of symptoms on all the gadgets in the house - phones and computers. It took me a few hours to understand the problem but since the router work that I did I've seen no recurrence - though I will say I'm getting more server busy messages from RedCafe than normal.
A common variant of the problem is Google and similar search sites getting diverted to Conduit Search either by changes in browser setting, entries in their hosts file, or by the individual machine (or the router) being switched to use a hacked or spoof DNS server. It wouldn't be a surprise if certain advertising server addresses are now being diverted as well.
I guess the other "why not everyone" thing is that context/target sensitive advertising may mean it really is just some ads that have something nasty embedded - right now my browser is busy trying to sell me flight tickets, cameras and flashAir cards but I'm sure that's not true for everyone.