What's the difference between paid placement and paid inclusion?

Paid placement: Web site owners pay to have their site included and ranked higher than other results in an index of similar or competitive content. The web site owner typically will bid on certain keywords or phrases. Paid placements are usually marked as "Features Listings," "Sponsored Links," etc. This type of service is offered by Overture, Google, Ah-ha, and LookSmart.

Paid inclusion: Guarantees scheduled indexing, and has no effect on ranking. The costs of of paid inclusion is usually per URL to be included and guarantee a year of inclusion. This type of service is offered by FAST, Inktomi, AltaVista, and the LookSmart and Yahoo! directories.