Search engine marketing refers to the use of paid advertisements that appear on search engine result pages. Marketers bid on keywords that trigger paid advertisement placement in search results. These leads are called Paid Leads. The single largest provider SEM vendor is Google through its Google Ads product. Google Ads allows marketers to identify keywords that match the demographic they seek and to place bids on those with the best fit. Facebook allows marketers to run campaigns through its Ads Manager platform. LinkedIn’s service is Campaign Manager.