What's the deal with these link sites?

[Jim Nazium]

Sometimes when I'm shopping for a new bass I just go to Google and type in the make and model I'm looking for. Inevitably some of the search results will have a name like "awesomebassdeals.com" or "coolguitars.com" but when I go there it's just a bunch of links to ebay auctions. How do they make money from these sites?

[Dirk Diggler]

Just like here, advertising and click thru on links.
A lot of those type of sites are also dynamically created on demand.
Dirk