Some people prefer to move older stories to an "archive". You can actually see that on quite a lot of (non-Geeklog) sites.
I never understood that idea myself - it doesn't hurt havening the old stories around, IMO, since they drop off the index page automatically anyway. But in case you prefer that archive approach, you can have that now. And if you don't, simply ignore it ...
Auto-deleting stories, on the other hand, is useful, e.g. for "I'll be away"-type of posts or other posts that you won't need any more once their due date is up.
bye, Dirk