Self Cleaning Bookmarks

So, I'm sorting back through a bunch of old bookmarks in my Diigo account right now.  I've got some bookmarks that are 10 years old.  Sites that I imported from my browser's bookmarks and which date back to college.  I'm finding several sites that are now dead links.  No big deal.  But it has occurred to me that it would be pretty snazzy if Diigo (or other bookmarking tools) had a self-cleaning function.  I would think that it would be a pretty easy program to write that would run through all of your bookmarks, "click" to the sight and discover if it's an active link or not.  If not, the next time you log into your account, a message would pop-up saying you have broken links, do you want to delete them or try to fix them. 

How cool would that be?