Stack Overflow is a Q&A tool imposing a certain structure in the way the dialog is handled between OP and the rest of the community.
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
I haven't used iTunesU, but every Coursera class has its own Q&A discussion forum. I think it's better to use that resource along with other people who are in your class rather than try to start a discussion on a Stack Exchange site.
If you prefer the Stack Exchange Q&A format, use one of the Stack Overflow clones.