Infinite scroll is enabled on your blog. You can disable it on this page > Settings > Reading and set the number of post you wish to appear on the front page of the blog.
Blog pages show at most ____ posts
enter the number of posts you want to display
scroll down to:
To infinity and beyond ___ Scroll Infinitely
(Shows 7 posts on each load)
remove the checkmark
scroll down and click "save changes"
Disabling the infinite scroll feature to get rid of the pop-up in the footer results in a "Load More Posts" tab, and you can't disable that "Load More Posts" tab from appearing and have "previous post" and "next post" links, without the Custom Design upgrade. http://en.support.wordpress.com/custom-design/