Make them text or basic images like JPG or GIF (but then they couldn't hijack your speakers and blow your ears off, what fun is that?) and NO FLASH ADS because flash zero days are one of the biggest attack vectors out there
I agree, as does the featured article: "In addition, users who dislike the distraction of Flash-based advertising can install browser add-ons that just block Flash content, such as Flashblock for Firefox and Chrome." Flashblock for Firefox is the middle ground that I've been choosing for years. And before that became available, I had a practice of hosts-blocking any ad server that served SWF on a site. Slashdot was surprisingly one of the first sites I saw that showed an SWF ad for Splunk log analysis software, and whatever server was serving it was the first to get 0.0.0.0'd in my hosts file.
(but then they couldn't get "teh big bux" for having the most annoying Goatse of ads spewed on their pages)
Yeah, the article quotes the VP of some web advertising consulting firm who whines that static ads have an unviably low CPM. Boo hoo.