Timestamp in wordpress is great.
But, I don't know if they'd fixed this in 2.5, but in earlier versions it would
ping all the defined services (Google, RSS, etc..) when you hit publish, no matter what was the time stamp was.
This would create broken links till the post is actually published.
There's a plugin to solve this though. I use
MaxWordPress Ping Optimizer.
This plugin also prevents
pinging after editing your posts. This is a big plus for me, since I constantly edit and improve on my posts after publishing.
ENJOY!