Online advertising includes email marketing, search engine marketing (SEM), social media marketing, many types of display advertising (including web banner advertising), and mobile advertising. Like other advertising media, online advertising frequently involves a publisher, who integrates advertisements into its online content, and an advertiser, who provides the advertisements to be displayed on the publisher's content. Other potential participants include advertising agencies who help generate and place the ad copy, an ad server which technologically delivers the ad and tracks statistics, and advertising affiliates who do independent promotional work for the advertiser.
In 2009, Bluehost introduced a new feature called CPU throttling. CPU throttling (at Bluehost and similar hosting services) refers to the process of reducing user's CPU usage in whenever the particular user is pulling "too much" server resources at one time. At that particular time, Bluehost would freeze (or drastically reduce) client sites' CPU usage substantially. This effectively shut down clients' websites hosted on the Bluehost server for several hours throughout the day.