ClickZ: Paid Inclusion Beats PPC in Many Markets
ClickZ's Fredrick Marckini does the math on paid inclusion marketing, determining where the inflection points are for positive returns when adding "PI" to the search engine marketing mix. In most cases, PI seems to pay for itself. Only Yahoo continues to offer the service, as other search engines have stopped the practice for fear that it will allow marketers to make search results less relevant to users.