Extensions are nothing but extending the use of something with an ease. Exactly in the same way, browsers too have extensions for some additional purposes. Initially, Google Chrome did not have extensions associated with the browser. Some of other browsers like Opera, Mozilla and etc.. had extensions associated with their browsers which were mostly used only because the using or accessing some of the stuffs/items in account of browsers decreased a lot of user work. I mean Extensions made users to use and access some of the things within a browser in an easier way.
Now, The most fastest Browser named GOOGLE CHROME too have extensions associated with it. Lots of extensions are there for this browser. You can see all the extensions which can be associated to GC browser from this site. https://chrome.google.com/extensions
There are many extensions as you saw from the above link but here, i like to tell only about one extension named FastestChrome - Browse Faster - Version: 1.4(Save time by speeding up repetitive tasks. Get auto-loading of next page, improved searching, and more. Enhance your productivity!).
This extension is actually used for many purposes. One small example can make you understand what exactly this extension do. Everyone search for something from best known search engine GOOGLE. It gives out the results soon and it will be organized in the form of pages. If u have to go for next page, you have to click on the link '2' or 'Next'. This will be not handy if you have to see results of many pages. You wish to have a better solution for this and the solution is given by the above extension. As you scroll down, the browser automatically loads next page and it also displays the page number in the Page Header. This extension is not only applicable to google site, it works on all sites which will have the "Next" page options. So, it is really very much handy and it is better than clicking on the 'Next' link by scrolling down to the bottom of the site.
This post is completely used/applicable only for the users who use GOOGLE CHROME web browser. Thank you.