Definition
Paid inclusion (or guaranteed inclusion) refers to the process of paying a fee to a search engine in order to be included in that search engine’s search results.
Paid inclusion does not impact rankings of a web page; it merely guarantees that the web page itself will be included in the index.
These programs were typically used by websites that were not being fully crawled or were incapable of being crawled, due to dynamic URL structures, frames, etc.[1][2]