Google Chrome extensions are programs that can be installed into Chrome in order to change the browser's functionality. This includes adding new features to Chrome or modifying the existing behavior of the program itself to make it more convenient for the user.
Examples of the type of functionality that a Google Chrome extension can add to Chrome includes:
As you can see, extensions offer a wide range of extra functionality so that you can perform tasks easier or get more out of the web sites you visit.
Unfortunately, while most Chrome extensions are beneficial, there are some developers that create extensions that modify the behavior of Chrome in a negative way. For example, adware developers may install Chrome extensions without your permission that inject advertisements on to web pages that you are viewing, change your search provider to a site under their control, change the new tab page, or hijack your home page.
How you use a Google Chrome extensions depends on the particular extension. Some extensions work in the background and perform particular tasks automatically. Other extensions will add menu options to the menu when you right-click on a web page as shown below.
Most extensions will also add small icons to the right of the address field in the browser. These icons can be clicked on or right-clicked to access the functionality of the extension. You can see an example of extension icons in the image below.