In reply to Ray.

For the average user, that's usually no problem, but it's not always as simple as un-checking a box. There are a few reasons I believe this is useful.

1) When you're going to be away from your site but need to have a sticky post up for a limited amount of time.

2) When you run a large site publishing many articles a day. Sometimes, you lose track of those posts in the admin (stickies don't go to the top there).

3) Uncommon uses of sticky posts on large sites that need time-sensitive stickies.