About 90% of what you see on a lot of web pages actually comes from "adservers" (with a variety of site names) and they can be a real P.I.A. A couple of sites I visit occasionally (but as infrequently as possible) spend about 4 times as long loading the script for the "ad inserts" as to download the page, and then about two thirds of the time one of the "ad links" fails to serve up the insert and the page I want to look at disappears into a "link failure" or "IE cannot open" error message - because the AD-PIMPS selling the ads can't/don't provide a working/workable service.
(One site that I refuse to identify but who's initials are washingtonpost.com has been particularly annoying recently.)
I do "not get them" in my regular browser, but then I use IE.