startup company (later Overture, now part of Yahoo!), presented a pay per click search engine proof-of-concept to the TED conference in California. This presentation and the events that followed created the PPC advertising system. Credit for the concept of the PPC model is generally given to Idealab and Goto.com founder Bill Gross. Google started search engine advertising in December 1999. It was not until October 2000 that the AdWords system was introduced, allowing advertisers to create text ads for placement on the Google search engine. However, PPC was only introduced in 2002; until then, advertisements were charged at cost-per-thousand impressions or Cost per mille (CPM). Overture has filed a patent infringement lawsuit against Google, saying the rival search service overstepped its bounds with its ad-placement tools. Although GoTo.com started PPC in 1998, Yahoo! did not start syndicating GoTo.com (later Overture) advertisers until November 2001. Prior to this, Yahoo's primary source of SERPs advertising included contextual IAB advertising units (mainly 468x60 display ads). When the syndication contract with Yahoo! was up for renewal in July 2003, Yahoo! announced intent to acquire Overture for $1.63 billion. Today, companies such as adMarketplace, ValueClick and adknowledge offer PPC services, as an alternative to AdWords and AdCenter. Among PPC providers, Google Ads (formerly Google AdWords), Microsoft adCenter and Yahoo! Search Marketing had been the three largest network operators, all three operating under a bid-based model. For example, in the year 2014, PPC(Adwords) or online advertising attributed approximately US$45 billion of the total US$66 billion of Google's annual revenue In 2010, Yahoo and Microsoft launched their combined effort against Google, and Microsoft's Bing began to be the search engine that Yahoo used to provide its search results. Since they joined forces, their PPC platform was renamed AdCenter. Their combined network of third party sites that allow AdCenter ads to populate banner and text ads on their site is called BingAds. PPC Statistics Customers are 50% more likely to purchase something after clicking a paid ad. SMEs spend $108,000 to $120,000 annually on PPC ads. 57.5% of users don't recognize paid ads when they see them. Click Bots and Fake Traffic Cost Online Advertisers $35 Billion Legal In 2012, Google was initially ruled to have engaged in misleading and deceptive conduct by the Australian Competition & Consumer Commission (ACCC) in possibly the first legal case of its kind. The ACCC ruled that Google was responsible for the