What game console do I buy? Well, the one my friends have, so we can trade games and play against each other! What club? The one my friends go to...we like the same music (roughly), and have the same general style...we probably even like the same kinds of girls. So, IM is infinitely more valuable than the service you describe even if only one or two friends are active right now. If it's not expertise that you're brokering, you've got nothing of value, as far as I can tell.
A Google search about game consoles will turn up thousands of random opinions from strangers about just about any subject (particularly game consoles, but clubs also get talked about, etc.), so without some sort of expertise, you're just doing a really inefficient and slow Google search.
Now, I'm not saying brokering expertise is an easy business, but I can at least see value in it. I can't think of any good use cases for a dedicated "trivial questions with easy answers" system.
I'm happy to be wrong. Maybe you should build a prototype this weekend and see how people react...you'd probably be able to get some media for it, since all of the big answers services have been shutdown or shuffled off into a corner to die quietly. If it looks cool, you'd be able to get a crunch and maybe some hits from design blogs. If you use a funny language (Smalltalk or Erlang or something) you can get some hits from that. It costs nothing but time to try it.
But, it's not an idea I would be willing to invest any time in. (Although, I did just invest fifteen minutes or so in my various responses to your query about it.) ;-)