To take the opposite view, I have not experienced (so far, fingers crossed, knock on wood) the Dominic Effect in terms of traffic.
On a medium size site (2,000+ static pages) I find with hard work at keeping Google friendly pages (and I do not mean spamming) and using legitimate techniques to attract freshbot my referrals continue to increase (the only drop I had was March which was an industry wide pattern in my area and a function of a general drop in consumer interest).
I find that the best advertising investment I have ever made is the trivial annual sum for Inktomi inclusion and that effort put into optimization generates a steadily upward traffic trend from Google/MSN/AV, etc. on this 9 month old site.
I think as long as there is money to be made in the SE business from re-sale, etc. you will see "free" or minimal cost inclusion engines that can generate excellent traffic.