Youve probably run into the term plug-in while browsing the internet. This is because plug-ins have become a commonly used type of software. Their purpose is to provide the web browser with additional functionality. Basically, if a web browser cant display a certain type of content, a plug-in will do it for them. Each of the most popular web browsers allows the use of plug-ins. In fact, some of them, like Google Chrome or Mozilla, have their own marketplaces where they offer plug-ins. Those are the places where marketers can find a number of useful plug-ins for their work.