These firms advise companies how to design their sites to rank higher in search results or to bid more wisely on ad keywords or craft ad copy that will get clicked on more often.

FORBES: Magazine Article

Its algorithms can suggest the best price to bid for keywords, based on where the ad will appear on the results page and how many other bidders are present, factoring in constantly changing auction prices.

FORBES: The Keyword Keeper

AdWords helped revolutionize online advertising, offering marketers the chance to bid to display their ads when people searched for certain keywords on the Google search engine.

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