Over at WebmasterWorld they have two threads discussing the URLs Yahoo! uses in its organic search results (thread: 1 - 2).
The URL formats tend to mostly be in the following formats:
http://rds.yahoo.com/S=#######/K=keyword+goes+here/v=#/SID=e/l=WS1/R=#/SS=########/H=#/*-http://www.domain.com/
http://rds.yahoo.com/S= =#######//K=keyword+goes+here/v=#/SID=w/l=WS1/R=#/H=#/*-http://www.domain.com/
Sites includes in the Yahoo! directory get the SS= string added to the URL. Some sites have this OCS= string instead of the SS= string. The question is why? Still trying to figure it out...
