Great question!
When I proposed "Career Advice", I was thinking about all the "students" looking for career advise and their related questions that keep popping up at multiple SE sites but tend to be handled as off-topic for being "too broad", "opinion based", etc.
On the other hand, I frequently noticed that established professionals in the individual fields were willing and able to offer advise.
So, while the "experts" area is currently pretty much open, I think they include:
- senior students who have evolved beyond the "I'm not sure what courses to take" level,
- professors who know what it takes "to get there" and can provide related references,
- established professionals in the individual fields,
- companies and/or institutions who want to express and share what's on their wishlist related to the knowledge range of future employees,
- etc.
Of course, most answers will probably gain from included references (just like on other SE sites).
Whether the proposal is able to attract enough professionals is certainly an open question (like with all proposals), but I can imagine there's some interest on the "experts" side too.
Nota Bene: If it makes sense to broaden it, to narrow it down, or maybe simply "tune" the proposal's description... please feel invited to do so. Since English is not my native language, I'm sure the proposal's description could have been worded a bit more optimal and less confusing.