The vast majority of Devcoins are essentially mined by human creative work.

180M coins are distributed to people who earn shares for developing open source software, completing bounties, and writing on devtome, which pays 1 share for between 700 and 2000 words depending on the writer's quality. See sig for devtome link. The number of shares acts as the effective difficulty in earning devcoins, which is getting harder and harder (just like bitcoin mining). The coin has been around for 2 years but devtome is a fairly recent addition.

eg http://dvccountdown.blisteringdevelopers.com put round 33 in there with blank name in the search to see the most recently completed round.