Found this @ ESPN's Page2:

Patrick Lacey was the latest reader to ask about this: "Can you please shed some light on the whole 'Every guy on the team has to slap five with the guy on the foul line after every shot attempt, even if he bricks it' phenomenon? When did this start? When will it stop? It kind of just crept along, under the radar, until finally it is the most annoying thing in the sports universe that is simply not talked about."

(From what I can gather, it started about 15 years ago, because it never happens during the ESPN Classic NBA games from the mid-'80s. If I had to blame anyone, I'd blame those painful Knicks teams from the early/mid-'90s for starting it -- they were always reassuring one another after every screw-up. Plus, it's fun to blame the Riley Era Knicks for every revolting NBA development from the past ten years.)

Blame those Knicks for whatever you want, but they were a badass team. NO ONE went into the lane without getting punished in those days. They had a younger Oakley, Xavier McDaniel, a just-reaching-prime Ewing... man, they were nasty.

As for the reassuring bit... doesn't look like it hurt them... they went deep into the playoffs under that system.

BRING BACK THE CHEST BUMP

Damn wasn't it fun to see Mason and Oak chest bumping in the early 90's??

Problem is Camby would get injured for the rest of his career if he were to do a chest bump...

hahahah
probably
but hey I wish we still had it.
oh well