What are your most useful synchronous online facilitation practices?

Beth's Blog: How Nonprofits Can Use Social Media

I learned one from Nancy White when I took her online facilitation workshop. How does SL compare to these other tools and where does it fit on the gradient? And, how does a virtual world tool help or hinder effective online collaboration or a synchronuous online communication? This is interesting to me because Second Life is quite the opposite - there is a huge investment in learning the tools, there is no audio (although that is changing) and it is all visual.