Teamtastic members vote stories onto the popular stories page using the up/down arrows next to each story (if you can't see any arrows, you're probably not logged in).

We do ranking calculations throughout the day. We look for stories getting the most votes at the moment and put the top 20 on the page.

Stories need to keep getting votes to stay on the popular page. If they don't, or if people vote against the story, it will drop down the list and then drop off.

And, yes, we did nick this idea from digg.com and reddit.com