You can already do that with Reddit AskScience, AskHistorians, etc.
Or use the stack exchange familty of websites: Stackoverflow for programming, CrossValidated for stats, Cognitive Science, etc.
You go first! And before you say 'I'm not a professional', it doesn't matter if you don't know anything about anything - you probably know something about something, or you can ask an individual you know to volunteer, or you could pay someone to do it, or you can try some other clever solution that takes more than 5 seconds to think of.
For every person saying 'how about someone does Y', we need 10 people doing Y and seeing what happens. It's a great idea. Lots of things are great ideas. Enough with the ideas! Act!
Okay, I'll commit to emailing 7 people in a field, asking them to come to this site to answer questions.
First, I need to know what field people are interested in hearing from. I'll make a separate comment asking people what they'd most like to hear from.
Assuming I get decent levels of responses, I commit to emailing people doing this by the end of 2 weeks from now.
Could possibly be integrated with Lukeprog's call for people to offer their expertise to SIAI.
For my part: I am an International competitive debater and public speaking coach, ask me anything.
What specific subskills can you help a person learn in the domain of public speaking?
Do you think doing debate is a personal epistemic hazard (likely to encourage bad mental habits)?
Do you think doing debate impacted your personal social skills?
How much do you charge for public speaking coaching? Do you do free trials? Do you operate through Skype or only in person?
Would it be ok for specialists to just leave availability comments in this thread instead? That seems easier to find than multiple top level posts (although perhaps I am just bad at searching!)
Anyways, I know a lot about graphical models and causality. Happy to answer questions about these topics.
The Freenode and Efnet IRC networks have reasonably active math/physics/chemistry/neuroscience/... channels, with some of the channel regulars being experts in the area (often grad students and faculty). We've been trying to keep the Freenode ##physics channel in a decent shape for the last several years, but YMMV, depending on the area of interest, the time of day and random chance. More often than not, people just drop by for homework questions, but there are also plenty of more general discussions. The downside is that very little of it is posted online.
Is the suggestion to make a post in discussion, or in the comments here?
I'm happy to answer questions about machine learning / AI, although I'm afraid I don't have that many credentials beyond going to grad school at Stanford and having published a few papers. My focus has been on relationships between AI and cognition, and on incorporating computational constraints into Bayesian decision theories. I can also probably answer some questions about cognitive science.
I was suggesting making a post, because I doubt people are going to regularly check back to see if anyone posted here.
I really love this idea. Seeing what someone who knows about neurology has to say about cryonics has lowered my belief in how possibly efficacious it is and I'd like to update on more things like that.
In many previous comments, people call on professionals to answer questions about specific fields, like physicists, neuroscientists, economists, or computer scientists. There are many people in all these professions on this site willing to respond to questions, but most of the time none of them happen to read that comment.
As a way to fix this, I propose that people well-educated in certain fields volunteer to make an "Ask an X" post where they list their credentials and specialties, and anyone can ask questions about that field. Obviously, this would also be a good place to have a discussion between professionals in that field.
Another possibility is to ask people who don't mind being asked random questions to volunteer to be part of a list that can be posted to the wiki. Then, people could just PM that person directly.