As a nonce word, the pronunciation of maemo isn't something you can check in a dictionary. And given its provenance, I'd venture that most people first encountered this word in print, and not orally.
Should each vowel be pronounced, making this one really short three-syllable word? Could be.
Should the first syllable be pronounced the same as the month of May? Makes sense.
Or does a followed by e represent the ae diphthong, which if really stretched out would be “maaa-eee” but which English speakers consider a long i: “my”? Well, yes, why not?
I've heard all these pronunciations used at OSiMWorld the past couple days, plus the “two-and-a-half-syllable” variation (really short e) and the “silent a” (“me”-mo).
Now some might argue that, as a trademark, Maemo's pronunciation is properly decided by Nokia. But I figure if Sony couldn't dictate that its corporate name be pronounced “sunny” (intended as a slang-y spelling of “sonny”-boy), that argument doesn't hold water.
Someone said this evening that “I expect it to be 'may-mo' but I think of it as 'my-mo'.” Me, too.
The first Maemo Summit begins Friday in Berlin. Since this event is birthing the Maemo Community to formally represent all the non-Nokia participants involved in our pocket revolution — that would be us enthusiasts, the users and developers — I'd like to point out that one good reason for preferring “my-mo” is simply how it subliminally confers this new status. Maybe Nokia has the trademark, but it is sharing ownership with us. With me. And now it truly is my Maemo.