Yes, we all know Google is probably going to be #1 - as someone looking for "Santa Monica Plumber" isn't opening up the physical Yellow Pages book anymore (well probably 99%) nor are they going to some site like 'local.com' (at least not everybody).
But there are still a gazillion sites out there: SuperPages, YellowPages, Merchant Circle, etc etc etc. I would suspect that comparatively these sites are from an actuall traffic generation standpoint virtually insignificant compared to Google+Bing+Yahoo. Yet they all want to see some sort of premium service and there are SEO companies selling you services to keep your data updated on all these sites.
Yes, having local citations can help your SEO on the major search engines, but that's not the point of this thread. What I'm asking is where's is the pie chart showing the share of ACTUAL TRAFFIC generated from all these sites? Is it just something that makes these sites and the Local SEO Service companies cringe at too much so no one has been brave enough to do a study? Am all I left with is checking any property I can think of on Alexa?