In the audiobook for Daniel Suarez's Daemon, Jeff Gurner pronounces it dee-mun. I changed the way I pronounced it after listening to that book. Most people I know pronounce it day-mun, though.
I'm listening to it now. Quite clever, and a real page-turner! The writing and story-telling are awkward, and its plot holes are numerous, but fun concept for the Hacker News crowd.
