I run several websites, and the sole reason you do what's been done here with ebay linking, is for monetary reasons.
If there wasn't a way to make money from it, as a website designer/programmer, you simply wouldn't normally bother.

And as wilfy has mentioned, the main reason alot of the ebay threads have view counts, is people clicking on them simply to clear them of their unread posts. The way around that is to select the ebay forum, then select "Mark this forum read" from the "Forum Tools" menu. All unread ebay posts disappear from your unread/new posts list.