Pay-Per-Click Advertising (PPC)
These advertisements are also called sponsored links or sponsored ads and appear next to or above the organic results on search engine results pages (SERPs), or where the site owner chooses on a content site.
Third party websites that host PPC ads display an ad either when a keyword query matches an advertiser's keyword list, or when the site displays relevant content.
Google AdWords, Yahoo! Search Marketing, and Microsoft adCenter are the three largest network operators with all three operating a bid based, Cost Per Click (CPC) model. Price paid varies depending on the system, the relevance and the level of competition for a particular keyword.
Average ROI : £12.98 for every £1 spent on PPC.