Advertisers may also deliver ads based on a user's suspected geography through geotargeting.
A user's IP address communicates some geographic information (at minimum, the user's country or general region).
Many common online advertising practices are controversial and increasingly subject to regulation.
Online ad revenues may not adequately replace other publishers' revenue streams.
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 2011, Internet advertising revenues in the United States surpassed those of cable television and nearly exceeded those of broadcast television.
For example, two of the predecessor networks to the Internet, ARPANET and NSFNet, had "acceptable use policies" that banned network "use for commercial activities by for-profit institutions".
The first widely publicized example of online advertising was conducted via electronic mail.
On , a marketer from DEC (Digital Equipment Corporation), Gary Thuerk, sent an email to most of the ARPANET's American west coast users, advertising an open house for a new model of a DEC computer.