Google Analytics (GA) is a free service offered by Google that generates detailed statistics about the visitors to a website. The product is aimed at marketers as opposed to webmasters and technologists from which the industry of web analytics originally grew. It is the most widely used website statistics service, currently in use on around 57% of the 10,000 most popular websites. Another market share analysis claims that Google Analytics is used at around 49.95% of the top 1,000,000 websites (as currently ranked by Alexa). GA can track visitors from all referrers, including search engines, display advertising, pay-per-click networks, e-mail marketing and digital collateral such as links within PDF documents. Integrated with AdWords, users can review online campaigns by tracking landing page quality and conversions (goals). Goals might include sales, lead generation, viewing a specific page, or downloading a particular file. These can also be monetized. By using GA, marketers can determine which ads are performing, and which are not, providing the information to optimise or cull campaigns.