Phil Edholm, the enterprise CTO at Nortel, has an uncanny capability of synthesizing complex issues.
Across multiple blog postings, he talks to a simple graphic of what he calls Communications Dimensions.
I like the way he breaks out event and social driven interactions. I see these very much as two sides to the unified communications coin.
IBM has embraced this view with their Unified Communications and Collaboration (UCC) strategy, as has Nortel who have led the way in leveraging virtual reality for business with their web.alive solutions.