I've noticed this too, and it's an annoying trend, so let me make the official policy clear:
##If a question about an Apple product is on topic for Super User as defined in the the FAQ, then it should stay on Super User
If a user comments saying that questions about OS X should be moved to Ask Different, kindly reply with a link to this meta post explaining the official policy. If the users argue or continue telling users to migrate their questions, flag the comments for a moderator and we can step in to remind them.
We want more OS X questions, not fewer. In fact, there is no reason why Super User shouldn't view the inception of Lion as a good opportunity to bring new visitors to our site as well.
The only times a user should be encouraged to have their question migrated to Ask Different are if the question is one of the following:
- off topic here, but on topic there
- getting very few views and no good answers, and you believe it might get better answers there
- the user who asks the question requests it to be moved because they think it would do better there
Ask Different is a great site. They have a good community of knowledgeable Apple users. However, it is their own responsibility to recruit users, and Super User is not really the appropriate place to do that. You don't see prolific Super Users going over to Ask Different and posting "actually this question is on topic for Super User, you should move it over there". Furthermore, some users choose SU over AD because they are more familiar with SU, or because of the differences in the feel of the community. This choice is up to the user.
In addition to being rude to the SU community, it is also rude to the new users asking the questions: if we are trying to recruit new users, then by arbitrarily shuffling their questions around to other sites — when they're on-topic here — creates a confusing and irritating user experience. We want new users' interactions with the Stack Exchange community to be positive, and jumping on them for posting in the right place is more likely to drive them away from Stack Exchange completely than to convert them.