Kaa-ching is nowadays on various forums and irc the alias for Klaas van Gend.
Origin of nickname
Klaas originally always used kvangend as login - until he realized that 'vangend' means catching in his native language, Dutch.
For about a day, he changed his nickname to kcatching, and then switched over to kaa-ching. It looks better and also has some bearing on his job (At the time, he worked in the sales organization of MontaVista).
Several people already confused his new nickname to be Chinese, which of course adds to the fun.
Focus in this wiki
Klaas has been spending most of his time in this wiki on the various books in the Category:Books category.
Klaas is the lead developer for the open source user land project to bring support for UMTS to Linux: umtsmon.
Professionally, he has been spending significant effort in promoting embedded Linux and more specifically real time Linux.
He also is a board member of the NLUUG and is one of the co-organizers of the Embedded Linux Conference Europe.