Web sites without advertisements in the middle of the body text still exist, such as wikipedia.org, tvtropes.org, and even slashdot.org once you've maxed your karma for a while.
I never see any of these spamvertisements that people are referring to, no matter what my karma or status is on this or that site.
Mostly that's because I use privoxy, which does 99% of the adblocking I ever want. However, I do on rare occasion play the "Block Content" or even "Edit Site Preferences" games in Opera. I think of "Block Content" as something of a first-person-shooter video game to shoot down intrusive spamverts.
I am so allergic to spamvertising of all sorts that I really can't read generic stuff on the web using somebody else's browser setup without going pretty completely batshit. I've been known to cover the stupid jumping pictures with giant postits or a taped on piece of paper. I am no more capable of reading static text while something is juggling screaming cats right in front of my face than I am capable of reading a book while a wailing banshee blasts out my eardrums from 2" away.
It's like how people with Tivo report that when they're visiting someone else's home and see a TV running with commercials on it, their first thought is something like "Huh! That TV's broken." That's exactly how I react when I come across someone else looking at the web with all its spammy in-your-face attention-seeking whinings: that their browser must be broken or something.
Disabling moving GIFs and sound by default is really mandatory, and really probably plugins, too, unless you have some other mechanism to block them. I've even been known to turn off javascript on specific sites just so the dumb things stop moving around on me. Even tooltip popup balloons can be maddening: just shut up, get out of my face and my mind, and let me read in peace, damn it! I would never read a book or magazine that had a loud screaming baby built right into it, and it simply astounds me that anyone puts up with this sort of outrageous assault.
I truly think that without the the serene freedom from the otherwise relentless spamvertising that this privoxy+opera combo gives me, I'd've long ago gone medieval and probably completely postal on these rude assholes. It's criminally abusive what they try to do to us.
Nobody has the right to strap you in a seat with your eyelids sewn open so they can steamshovel their spamverts into you. We call that assault, and nobody but nobody should put up with it. It's like the insulting "can't fast-forward through ads" property on some DVDs and some players. Their rights stop long before they reach my mind: I am not their prisoner, so go find some other sheep to bugger.