Google AdWords is the biggest and the best, but it has not be around the longest. AdWords went mainstream in 2001 and has dominated ever since. The traffic potential is highest because Google gets 71% of search engine share according to Nielsen and ComScore. One drawback is clicks are typically more expensive. Website: www.AdWords.com
Yahoo! bought Oveture’s cpc search engine back in 1999 and integrated it into Yahoo! search. They then changed the name in 2005 and added many more features calling it Yahoo! Search Marketing. In 2007, Yahoo! introduced Panama, which nearly duplicated many of the features of Google AdWords, eventually even matching the structural nomenclature in order to make transfers less confusing. Yahoo! is great for retail and many product-based sites, whereas Google rules with B2B and services. Website: www.MarketingSolutions.Login.Yahoo.com
Microsoft started their own pay-per-click platform back in 2006. Their functionality was better than Yahoo!’s from the get-go. The only drawback, traffic could be low if advertisers were trying to be too narrow. They have since increased functionality and transfer ability in a big way. They offer excellent support. I have been to their office and met some of their team members. Website: adCenter.com.Microsoft.com
ASK.com, formally AskJeeves.com, has has pay-per-click longer than you might imagine. ASK.com is also a search partner of Google, so you can have your ads appear on ASK.com if you are an AdWords customer, although from experience they seem to give their direct customers better placement, understandably. Website: SponsoredListings.Ask.com.
