I found Lisa B Marshall's podcast on "presentweeting" fairly clear on how to take advantage of Twitter during a presentation. How to Use Twitter to Supercharge Presentations.
While this discussion is specific to using tools that automatically post tweets for you while you go through a slide-based presentation, it should apply conceptually to just about any situation where the presenter cannot be in the backchannel: they are the front-channel after all.
So, what does Lisa B Marshall recommend? Some very simple things - almost obvious, but I have never seen these stated anywhere. And the only "presentweeting" I've seen is people tweeting that they are "testing presentation tweets."
- Tweet references and links at the appropriate point in the presentation (so people don't have to go looking)
- Tweet additional information beyond the expected content to enhance the presentation for those in the backchannel
- Tweet out questions or polls
- Engage beyond the immediate audience
- And don't forget to use recommended hashtags
Since the presenter cannot possibly be reading and responding to content in the backchannel, the only thing she can do is drop in useful content as the discussion moves along. That's exactly the point of the tools out there that let you tweet at certain points in the discussion.
A major caveat: Most presentations in the world are given internally, so this specific version of using Twitter to expand the experience may not fit. But wouldn't it be great to use something like this to expand what you are doing on a webinar or or situations where the backchannel could use some energy?