I don't see a reason why would Yahoo Sponsor Link's PR would increase. However, once the site is Yahoo Sponsor, site will have more visibility and if it is any good, people are likely to link back. So Yahoo Sponsor might not be increasing PR directly - but it can still effect on long term.
P.S.. Site being good is the *key phrase* here :)
mosley700
6:52 am on Sep 23, 2002 (gmt 0)
If the PageRank of the page where the sponsored listing appears is high ( and if it's Yahoo!, it's high ) then it should certainly boost your PR.
mosley700
6:55 am on Sep 23, 2002 (gmt 0)
One thing to consider, Google also notices when a link disappears. So, if you ever choose to discontinue a Sponsored Listing in the Yahoo! Directory, it could hurt.