About the New Tab page
Firefox makes it easier for you to access great content the moment you open a new tab by displaying your most recently and frequently visited sites along with popular web content. The New Tab page is the default Firefox start page unless you have set a different home page.
The first time you use Firefox you'll see links to top-ranking websites and popular search engines. These are eventually replaced with links to frequently and recently visited sites from your browsing history.
You can customize this page the way you want. Visit the following articles to see how: