[joegreen]

Well, I don't have similar experiences with SO. Sometimes I feel that easy questions are being answered very quickly by many people because everyone wants to get reputation points quickly, but difficult questions are often left unanswered forever as they require a lot of effort and don't bring as much reputation to the answerer (as their potential audience is not so wide).

[junto]

That's what the bounties are for.

[nanospeck]

Yes for questions with very less audience, you can offer a a bounty after a limited duration (3 days if I remember). You will have to give away your points as bounty. If you do not have enough points to give away, sign-up on other Stack Overflow affiliate sites that give you 100 point for every sign-up. And give it out as bounty.