Olark is a customer support tool that you can use to offer real-time chat on your website or in your web app.
We use it for our tool (click to see a demo of how olark is integrated in our site). It lives in the bottom right of the browser window and you can click it at any time to speak directly with a support person (in our case, myself and my co-developer). It integrates wonderfully into our app as well, allowing us to pass username and email address to us in chat, and Olark itself lets you know what URL a user is viewing so we can click on it and see what they see. It also monitors for idle time, supports Jabber/Gtalk, and a host of other useful features that make it a great little piece of kit.
It strikes me that something like Olark might offer an opportunity for moderators to nip some issues in the bud in terms of new user confusion or people wondering whether their question would be a good fit (or any number of other issues that may come up). It would also allow moderators to provide basic support in how to use the site.
I've heard (this is anecdotal) of people having trouble with signing up using OpenID, for instance, or with the initial understanding of the Q&A model, and this might give us a chance to help those folks out and learn more about what challenges people face in using the site.
Let's face it, they aren't going to go to meta to ask about how something works, and there isn't really an easy to use help section in place anywhere (the faq doesn't count as it's mostly about rules, not about how things work). Chat isn't an option either as it's only usable once you have an account. And we must remember that 90%+ of visitors are are lurkers who aren't going to actively participate, but might be willing to ask a non-committal question without having to sign up.
Is this an option worth considering? Or are moderators not "customer support" and should they not be involved with such roles? (If so, perhaps StackExchange Inc. could consider using it internally?)
Note: I'm not advocating using Olark per se, just that the functionality and usefulness it could add to a community are beneficial. Don't focus on Olark, focus on the added value.