Online yellow pages are essentially what they sound like -- an Internet version of the portion of the phone book known as the yellow pages. The phone book yellow pages are distinguished from the white pages in that one can look up businesses by business category, such as dry cleaners or video rental, without having to know the name of an establishment. Online yellow pages are similar, but offer much more customizable searches. For example, the user may search by business type or name and may specify the geographical location to be searched. Different online yellow pages offer different options to the user.

There are many advantages in using online yellow pages over the paper version. Besides being able to tailor each search to the user's specific needs, online yellow pages cut down on paper usage. They also have more up-to-date information, as an entire reprinting is not required to change a company's address or phone number.

Online yellow pages typically include a link to a mapping site with directions to each business. The user can also usually type in his or her address and request listings within a certain distance. In addition, it is common for online yellow pages to provide links to the website of each company it lists, where the user can find additional information without calling or visiting the business.

Like other Internet services, online yellow pages compete with each other for web traffic. Therefore, they may offer unique features to attract new users and business clients. Online yellow pages are generally free to use and make their money from advertisers. One special feature offered by some online yellow pages is a photograph of the front of each business establishment listed. Some online yellow pages offer user reviews and ratings of their listings.

A relatively new offshoot of online yellow pages is mobile yellow pages, available on various WiFi-enabled mobile devices. Mobile yellow pages take convenience to a new level, as the customer can search for a business on the go, without the need of a phone book or a computer.