Similarly to people telling the OP to [ask their question on Apple.SE][1], even if it's on topic here on SU, I think that there's a general problem with comments like the following:

> This should be on Server Fault!  
> Ask on Stack Overflow!  
> Try apple.stackexchange.com!

These comments do not serve any good purpose for several reasons. 

- They leave the OP confused about where to ask. Was he wrong asking here? Doesn't that even come off as rude?

- They do not have an actual effect on the state of the question. It's not automatically being moved.

- They will force the OP (especially in the case of new users) to re-post their question on the other site, therefore cross-posting. If the community decides that the original question is good to stay, we have a cross-site duplicate. Or, even worse, the question is later migrated.

What, specifically, can we do against this?


  [1]: http://meta.superuser.com/questions/2967/is-it-okay-to-inform-users-to-stop-promoting-apple-se-when-a-question-is-fine-to