Online advertising is a form of promotion that uses the Internet and World Wide Web for delivering marketing messages to attract customers.

One major benefit of online advertising is the immediate publishing of information and content that is not limited by geography or time.

Another major benefit of online advertisment is the efficieny.For example, AdWords, Yahoo! Search Marketing and AdSense enable ads shown on relevant webpages or aside of search results of pre-chosen keywords. The advertisers pays only when someone clicks on their ads.