I get a percentage of my time worked - say I bill at $575/hr and bill a client 10 hours for $5750, I get 40% of that, so $2300. If it is my case or I originated it, I get another 25%, so if I billed that 10 hours on my own case that I brought to the firm, I'd actually get 65% of my billings or in that case $3,737.50 for that same 10 hours. The third scenario is if I originate the case but some other guy bills on it, I only get the 25%. So if I bring in a case but my associate works on it and bills 10 hours at $375/hr, I'd get $937.50 for him working on "my" case.
It incentivizes us to bring in cases and keep busy, the more you bring in and the more you bill, your income pyramids.