Effect Of Bolding On Click-through Rates

I'm interested in any studies regarding the effect bolding has on
click-through rates on a search results page.

For example, Ebay allows users to bold their listings for an extra
fee. How does this bolding affect click-through rates? I'm assuming
that the click-through rates increase, but I'm not sure.

I'm interested in an answer, but I'm especially interested in specific
sources (i.e. usability studies, etc) to back up this information.

Bold text attracts additional attention to a listing on a search
results page. eBay states that bold listings "are shown to increase
final price by an average of 25%". You can expect an increase of
click-through rate on the search results page for sure.

Are you interested in only "bold title" advertising?

I have a very special advertising technique at:
http://www.auctionmagnets.com/  Auction Magnets v2.0 - A highly
efficient advertising technique on online auction sites.

I can assure you that it is many-many times more efficient than
bolding, highlighting or any other advertising technique on online
auction sites. Works great! Pls. bookmark the page. It'll be finalized
in a few days. http://www.auctionmagnets.com