What is meta?
- Any Stack Exchange user can ask a question
- The community provides support, votes on ideas, and reports bugs
- Your voice helps shape the way Stack Exchange operates
Meta SO is also the global Meta for general network-wide SO/SE issues which are not specific to a single Q&A within the network.
If you look at the FAQ it states:
So it's not merely for questions about Stack Overflow. There will however be a separate Meta for Stack Overflow at some point.
I am adding one more point to answer of Bart.
Currently all feature request, bug reporting, Promotions & Advertising Support is done on Meta StackOverflow. Hence it is shown on all site's footer. But this will be replaced in near future with MetaStackExchange