Not too sure, but what I do know is that it will not penalise you. So if it is not a trouble, you might as well ping it anyway. :smoker:
I have fund that the spiders where always coming very quickly when i use pinging, i use "all day sucker" for it, it is here somewhere on the board, i only do it with new sites/pages there is no need to ping old pages that have no new content. but for new content it is a great way to get the spiders coming. *disclaimer* getting spiders to you site doesnt mean you will get indexed soon, it just means that the SE know you're there, you always need to have good amount of backlinks to get indexed fast.
