Keep in mind that this is a ~35k user sample size of people downloading the TweetDeck beta application -- this is not "my mom" with an Android phone so I would

Keep in mind that this is a ~35k user sample size of people downloading the TweetDeck beta application -- this is not "my mom" with an Android phone so I would recommend you don't look at this as a valid sample for the overall Android market. The way to ensure the diversity remains compatible is by building a strong ecosystem around it that requires that compatibility -- the x86 ecosystem is a perfect example. By building applications that work with the Android mainline you create gravity forcing others to follow that path as well.