Online advertising is advertising on the Internet.

Online advertising is growing in popularity for many businesses to promote their products and services on the internet. With more and more of the world's population looking to the internet for news and information, it is no wonder that businesses are increasingly led to advertise online. It is cost effective and allows businesses a way to give more information to potential customers than most traditional forms of broadcast and publications. Online advertising technology advances are being made everyday that enhance what visitors would like to see.

Potential customers can find what they are looking for through searching keywords, categories, and browsing. Businesses can now interact with their visitors and make promoting their goods and services an enjoyable experience for potential customers. Businesses can also use the internet to keep in touch with customers through newsletters, chat, and promotions on their websites.

There are two sides to online advertising, a legitimate one and an illegitimate one. The legitimate side of online advertising includes search engine advertising, desktop advertising, online advertising directories, advertising networks and opt-in e-mail advertising. The illegitimate side is dominated by spamming.

Though the range of advertising options has expanded since in the commercialization of the Internet, the use of rich media and static images is extremely popular. The ever-increasing audience of online users will likely continue to be a major advertising market.