Anchoring sidebar link to a post

Hello,
I was looking at John Mayer’s blog and noticed that when you click on links in his “news archive” in the sidebar, the link is anchored to that post and scrolls you down to where it is. I’m pretty sure his site is not built in WordPress, but I was wondering if that would be possible in wordpress and how it is done. Is there even a plugin for it? I looked but couldn’t find anything. Any clues would be appreciated:-)