I can tell when AOL updates its search data from DMOZ dumps, my traffic bottoms out.
For whatever reason they don't add everything right away, so suddenly my site isn't listed. And then in a few weeks it pops up again and I'm again getting over 100 people a day from AOL for this one site.
It gets annoying.
I love AOL for the traffic it brings me, but the inconsistencies drive me crazy.