You know how every now and then you want to revisit a page in a while to see what's changed? Perhaps review if something has been added to a discussion? Maybe you're waiting for a beta to open or you have posted to a forum that doesn't have topic notification (or it is a regular website).
Simply click the reminder bear bookmark and customize when you want to get an email reminding you off the page. It's like a disposable bookmark, and lets you get on with more important things. I find it very liberating, try it out yourself.