Cost per click advertising (e.g. AdWords, Yahoo! Search Marketing) overcomes this problem by charging advertisers only when the consumer clicks on the advertisement. However, due to increased competition, search keywords have become very expensive. A 2007 Doubleclick Performics Search trends report shows that there were nearly six times as many keywords with a cost per click (CPC) of more than $1 in January 2007 than the prior year. The cost per keyword increased by 33% and the cost per click rose by as much as 55%.
Over time, the popularity of email marketing campaigns resulted in personal email inboxes that were overflowing with the latest and greatest offers. Email campaigns grew and people grew tired of them. Laws that allowed customers to unsubscribe breathed new life into email marketing campaigns as customers could easily pick and choose the companies they were interested in.