Depends. Without seeing your WP.com blog (since you’re not linking to it with your account) and which theme you’re using, we really can’t give you a definate answer though. Try adding a Page to your blog. Chances are that’s the answer.
please note that if your blog is not hosted here at wp.com, you’re at teh wrong site and you need to be over at http://wordpress.org since you would be running different software than we are here at wp.com.