It's hard to tell whether the search engines have done anything concrete against splogs, or whether the wave has passed temporarily. I say that because of what I see with referer spam - it's quiet for awhile, and then all of a sudden there's a wave of new crap (which is why the referer list for the CST blogs is no longer public). Anyway, I posted on the raw amount of splog content sitting in my aggregator awhile back (here), and I figured it might be interesting to have another look. So, I ran my test script again, using a cutoff date of October 22 - to see what's been coming up since then:

PubSub is still getting hit pretty hard (mind you, my script understates the damage - I'm looking only at Blogspot splogs here - eyeballing notes a few others). Seems like the other engines are addressing this problem a lot better, but again - you have to keep that leading caveat in mind.