An interview - even a public one - used to be a simple thing. Sarah Lacy of BusinessWeek just learned that things have changed.

The last few conferences I've been to have had a back channel - blogs, IRC, that sort of thing. Twitter has created an even simpler forum for a back channel, since it runs in a browser. So if your style creates a negative riff in the audience, it can just spread like wildfire - and that's apparently what happened today at the SXSW conference, when Sarah Lacy interviewed Mark Zuckerberg.

I started seeing some tweets about a negative reaction this afternoon, and now it's all over Techmeme. I don't think any interview done in front of a wired audience will ever be the same.