But chances are you're hearing a great deal more nowadays, but may still be a bit ... vague ... concerning what the fuss is all about.
Here's a piece from the Guardian's organgrinder blog that does a good job of laying out the whys and wherefores. It's worth a look.
I found the link through the BBC's Richard Sambrook, who blogged on the subject at Sacred Facts. I also liked what he had to say about staying abreast of online developments by participating.
Digital media is transforming society, but you have to get your hands dirty to really understand it. (Resist adopting the lofty "I have people to understand that for me" attitude I encounter which may just be a cover for fear of the new....)