A web directory is a directory on the World Wide Web. It specializes in linking to other web sites and categorizing those links.

Bid for Position web directory works much the same way, except that if a listing wish to be at top of the page he/she can increase the bids to the highest amount, usually about $1 in increamental.

Some bidding directories:

http://www.indexqueen.com
http://www.budgetdir.com
http://www.bid-for-position.com