If you're not even sure what paid search marketing is, let alone how to define click fraud, take a look at this brief introduction, then go back to the introduction for the rest of this In Focus on click fraud.
Second only to email, search is the most popular online activity.
The Search Economy
According to the Interactive Advertising Bureau’s April 2006 annual report on online advertising spending, search engine advertising accounted for 41 percent of online ad revenues in 2005. Once a mere rounding error in online advertising, search engine advertising revenues have grown to total $5.1 billion in 2005.
Advertising in search engines -- for example, the sponsored listings that show up on the right-hand side of the screen every time you run a search on Google -- have risen to become the largest portion of online advertising spending in recent years.
Google, Yahoo, MSN and many other search sites generate revenue by selling search listings that can be purchased by keyword or keyword matching in the form of "sponsored" results.
Listings are auctioned and advertisers compete for placements in keyword search results. Search providers also place listings on content or destination (e.g., Google AdSense) pages to generate revenue for content owners. These "contextual" or "content search" listings are also sold on a cost per click basis and revenue is shared between content owners and search sites.
Paid search is a good deal because advertisers pay only for clicks sent to their websites, and this performance-based model has proven itself suitable for many types of marketers. The rapid growth of pay-per-click advertising in search has meant tremendous economic growth for online advertising.