re: Poker & MY first post!!!
^^^ What jmill said.
Top players abuse rebuys worse than anybody. Daniel Negreanu is probably one of the most well known for doing it -- it's nothing for him to drop 20-30 bullets at $1000-$1500 each in a WSOP
rebuy event, especially if it's a long time until your table breaks. Basically the idea is you're spreading extra chips around the table that you feel like you can win back later if you're the better player.
In The Poker Tournament Formula, Arnold Snyder suggests that if your table is going nuts with shoving every other hand and rebuying, then you should do the same, provided you have the skills to play a solid game once the rebuy period is over. Rebuy as often as you can, and open up your shoving range a lot. You'll either steal a ton of small pots, or you'll double up a few times when inferior hands call your shove. You only have to do this a few times to chip way up, then with the add-on you're sitting on a big stack with a much better chance of going deep or winning. The rebuys go into the prize pool, greatly inflating it, making it that much more lucrative when you do cash/win. You just have to be able to change gears quickly and play a normal tournament after the rebuy period ends -- some folks have some trouble with that.