If you haven't been back to LinkedIn for a while, it's time to check it out again. I've written about it in full or passing before -- my favourite title is probably The first business plan with social networking features: LinkedIn, highlighting the fact that connecting people really is just one aspect of any such service.
So, why should you go back now? LinkedIn Answers. It lets you ask questions, answer them, recommend experts and links. It's definitely going through some growing pains, especially as there are no feedback loops in place to stop people from marketing or pitching rather than really asking questions.
I've been using it for the last 5 days or so....and it's addictive (bagged my first "expert" star in the Blogging category). The quality of the interaction is quite high, and I actually find myself browsing the questions. That has been my single biggest feedback about LinkedIn (not bad or good, just feedback): you go there when you need something, but there isn't anything that inherently draws you back. With Answers, that changes.
One thing I would like to see is increased open-ness from the system. Answers is exactly the sort of thing that should be out in the open, for many of the questions and answers. Any decent answer I post is likely of high enough quality that it should be posted out on my blog, available to the "open Internet". Having an account on LinkedIn is a fine barrier for interacting, but the content itself should be publicly permalinkable. Yes, LinkedIn is an identity system with reputation built in...wonder when they will connect to an open standard.
If you want to give feedback directly, I started a question inside Answers: Suggestions on how LinkedIn Answers should evolve.