Here's a bookmarklet, based on DeliciousSort, that will sort not just by total number of posts, but by the ratio of recent to total posts. It's trying to automate what I think I do manually, which is to skip the popular items that have been around for a while and only show the new ones.

--> DeliciousSortRecent

Works fine in Firefox, but not in Safari (because of the XPath bits, perhaps).

Update: Also looks good with's new sparklines.

Update II: Sparklines have gone, but the /popular page is now sorted this way by default, so there's no need for the bookmarklet.