Not to steer this thread too far off topic, but this may be relevant to some people's position in Yahoo serps... One of the benefits besides the traffic (which can be a big benefit if the directory page comes up for searches above your site on any of the major engines or if it's a very popular topic) is that it can help in certain niches to allow your site to be listed amongst the top ranking sites where it might otherwise be displaced by sites that are in the directory.
It seems that in certain niches the top X amount of results are derived by picking quality sites from the directory. For instance, we had a site receiving 3k uniques from Yahoo! for a few phrases - keyword1 keyword2, and a combination of one other word plus those two - which as soon as they did this manual shuffle was completely pushed down. The serps for all the keywords that we lost traffic for now are all 100% the same sites and see no rotation whereas just the day before that happened there would be a very consistent flux.
Another site which sat steadfastedly at #13 for a 15,000 searches/day (WT) query for months, went from #13 to #1 overnight after getting its first Yahoo! directory listing. Literally overnight and this was not an overall update.
So, there might be depending on your niche other reasons to be listed than the traffic. There are other reasons to value a listing too.