Sometimes, the content is loaded automatically when the visitor has scrolled to the bottom of the page. In other cases, the visitor needs to click a “Load More” button before the new content is loaded. Over the last couple of years, this type of pagination has gotten more and more common, to the point where you probably encounter it more frequently than you do the traditional pagination with links to the next and previous pages.
Infinite scroll is most commonly used on archive pages, like the blog archive for posts on a WordPress site. Occasionally, it is also used on single posts to automatically load the next post when the visitor scrolls to the bottom of the current one. The former type of infinite scroll is included as a module in Automattic’s plugin Jetpack.