When a topic or subforum has more than one page of posts or topics, different pages are automagically formed, so it is much more easy to navigate. You can find these page numbers directly below the title of the topic or the title of the subforum.
Because the forum gets bigger and more crowded it was time to add a small feature, highlighting of the page you are on. From now on, when a topic or subforum has more than one page, and you are not on the mainpage of that topic or subforum, the page number you are on will be displayed slightly larger than the others.
Enjoy the forum!