"View new posts since last visit" ?

I don't know if this is working properly, unless i'm not understanding the function of the link. When i arrive at this site I go into the forums and click on the "View new posts since last visit" link and it usually doesnt show me anything. As i go through the forum, people will post replies or new posts and they will show up under the "View new posts since last visit" search.

It seems like when i arrive at the forum, the my "last visit" field is being updated and therefore not showing me the new posts since I was here last. Just a thought.