So there have been an arse ton of new directories to hit the market.
I think listing sites in many of these will surely improve your Yahoo! and MSN search relevancy scores (or at least my own experiences have shown that), but I do not think many of them carry anywhere near as much weight with Google.
IMHO a disturbing pattern is emerging where the same directory owners own 2 or more directories which are easily identifiable as being related - especially since even many of the related directories have built significant portions of their link popularity from the same sources - and often even the same pages (while also registered under the same WhoIs information). Algorithms such as Hilltop mean the second "related" directory listing probobably counts for next to nothing in terms of its effects on Google's search relevancy.
The multi directory approach makes it far easier to make one of the directories a throw away...which makes the second similar directory do little to ensure added value over the first. If the registration data is the same for two directories and you do not expect them to drive much direct traffic then it might be worth just paying for listing in whichever one of the directories you think is going to be the main directory.
Lots of hate threads seem to be appearing about various directories (BlueFind, WebAtlas, and now RubberStamped)...often from other directory owners or close friends of other directory owners as well. Some people who run directories are also creating directory rating sites which are obviously going to be inherently biased.
When it comes down to it I do not think that search engines will need to do a ton of work to offset the effects various directories may have on search relevancy. The directory space is becoming hyper competitive (and thus likely providing diminishing returns for many directory owners) and many directories are making errors which will hurt themselves....sitewide payday loan links and top level penis pill listed sites do nothing to build brand or useful citation data.
If the search engines decide that data adds no value to their algorithm there is nothing that will force them to use it (as seen by what happened to SearchKing).
I have been trying my best to keep up with many of the directories, but eventually its going to be pretty darn hard to do. As the search algorithms continue to advance and new directories appear at an advancing rate I will probably have to look at other ways to keep up with new directories or abandondon the idea...at least in its current format.
I am starting to get the feeling that much of my time would be better spent learning and creating better ideas which effectively sell themselves, but for now I am still doing lots of submissions...
I am currently reading Blink and find it to be an interesting book thusfar. :)