Programming Poker on the internet
I do not remember whether I found IRC poker before or after I found Roy's C library for evaluating poker hands, but they both were a pleasant distraction from the Macintosh emulation and reverse engineering that occupied the vast majority of my time in the early nineties.
Hand Evaluators
Roy Hashimoto
Roy wrote C software to evaluate poker hands and to iterate through a deck to compute various odds. I, and others, found various ways to speed up Roy's code.
Mat Hostetter
Mat observed that there was a lot of information to be gained by viewing a hand as four 13-bit numbers (each 13-bit number representing the ranks present for each of the four suits) and then doing a bitwise-or of those four numbers. With Hostetter's Observation he was able to code up what was the fastest hand evaluator at the time. I did some of the grunt work.
Steve Brecher
Steve also did some poker programming and it was always a delight to bounce ideas off of him.
Michael Maurer and Brian Goetz
Michael and Brian created what was at the time the most elaborate library of hand evaluators and related software.
Andrew Prock
Andrew took on and conquered some of the combinatorical explosions that crop up when doing enumerations. He used techniques that generated perfect odds but called the enumerators far fewer times. His pokerstove was (and presumably still is) the fastest calculator of such odds.