People often get confused between PPC and PPI programs. PPI stands for Pay per Inclusion, whereas PPC stands for Pay per Click. One leading PPI search engine is Inktomi. You can subscribe to Ink by going to positiontechnologies.com. At this time the first URL costs $39 and $25 for subsequent URLs (anandsoft.com is not associated with positiontech or Inktomi). Here, you pay for including your URL into the search engine. Usually, the inclusion is time limited, and you need to renew the account every year. Another widely used PPI is mamma.com.  PPI is not performance based, in the sense that being included in a search index through PPI does not guarantee visitors to your website. It merely ensures that your web page is included in the search database. However, PPI engines crawl the paid web pages more regularly. This gives room for optimizing the web page so that the web page shows up on the top of search results.