Resarch In Motion has announced that they have two million BlackBerry subscribers, and that it doubled in less than ten months. that's pretty good, i remember a few years ago they said they had 400 thousand, which didn't seem like that much to me since everyone i knew carried a blackberry, and everyone i seemed to see on every plane i was on also had one.
for mobile developers, 2 million is a pretty small number. to put that in perspective, a small regional carrier like U.S. Cellular has about 2 million BREW enabled handsets.
the key is, BlackBerry users are definitely quality subscribers who are willing to pay for data services, and would probably also pay for quality appllications to run on the handheld. i hear from a lot of people that there aren't many applications for their blackberry and they wish they had more games to choose from...so if you are a developer, this might be a ripe market even though the numbers look small!