Working from fuzzy recall, so there will almost certainly be some inaccuracies:
In June of 2006, Simon Zadra set up the site. On the S@H boards his moniker was KWSN - Chicken of Angnor. The site was originally hosted on one of his systems in Austria, later moved to the KWSN server.
That was not too long after the first release of S@H Enhanced at the main project, there were optimized versions available but Simon wanted to set up a gathering place for those interested in making further improvements. He was also involved in development of Enigma 2.0 which forms the structure of the site, had experience building applications for both Windows and Linux, etc. Just after the site was set up, some generous contributors donated funds so he could use the Intel Compiler and Intel Performance Primitives for building releases.
In 2004 Eric Korpela had set up a Sourceforge project for enhancements to S@H, and a very skilled programmer named Ben Herndon was involved there. That effort had faded out before this place was set up, Ben brought over and made further improvements on much of the work he'd done there.
I was also involved from near the beginning, having also contributed some code to S@H Enhanced while it was being worked on at SETI Beta.
Crunch3r was also active; he's very good at building releases for almost any platform and figuring out which compiler and compiler options are best.
Anyhow, there were a sequence of releases starting with not much modification from the stock code, just rebuilding with the best tools and making separate builds for hosts with different capabilities, proceding to later builds with improvements by Ben, me, some imports from Alex Kan's work for Macs, etc.
That sequence ended at version 2.4. Ben Herndon had lost interest and bowed out. I had ported many parts of our code to the project. Crunch3r got involved in an argument on the NC forum and more or less moved away from SETI. Then Simon stopped posting here, and hasn't even visited since near the end of August 2007. He left no explanation and I don't know why.
Things were looking pretty discouraging until Jason and Raistmer got involved, now we're cooking. The AK_v8 builds are based on work Alex Kan did for Mac systems, S@H CUDA and Astropulse directly from the project sources but the latter heavily modified in the CPU builds and of course almost totally rewritten for the builds which use GPUs. Urs Echternacht has fired up the Linux, BSD, and Mac efforts, Devaster collaborates with Raistmer on some of the GPU work, there are occasional contributions from talented individuals like JDWhale, etc.
There are many others who have contributed in many ways. Testers are always a necessity without which development cannot be effective, Gecko's maintenance of the site has prevented it turning into an unusable target of spammers, etc.
Joe