Earlier this month, there was some discussion about Google having de-indexed free web directories. Most of the ones we looked at had not actually been de-indexed, but were not ranking well, but there were clearly some that had been de-indexed.
Since then, SEOmoz has been doing somde extensive data gathering, investigating the situation further. Kurtis Bohrnstedt, the company's "Captain of Special Projects" gathered a total of 2,678 directories, and only found 200 of them to be banned, but an additional 340 to be penalized (as in not de-indexed, but not ranking for obvious terms where they would be the only result that makes sense).
Still, that's only 540 directories out of 2,678. It would seem that there are a lot more directories in the clear, but Bohrnstedt thinks this is only Google sending a warning, and that there is likely more to come.
"That is not to say the ones left unharmed are safe from a future algorithmic update," he writes. "In fact, I suspect this update was intended to serve as a warning; Google will be cracking down on directories. Why? In my own humble opinion, most of the classic, 'built-for-SEO-and-links' directories do not provide any benefit to users, falling under the category of non-content spam."
I wonder if that includes directories that are apparently built for SEO and links and charge webmasters for the chance to get links, but offer some form of editorial oversight.
Interestingly, when this topic was being discussed a couple weeks ago, one webmaster said he had a paid directory he hadn't touched in years, which was unexpectedly seeing an increase in PageRank.