At Marketing Profs in Boston, Chris Brogan presented on "Successful Lead Generation in a Social Media World." The thing that impressed me is that he's using what seems like dozens of different social media applications.
He's a big fan of LinkedIn and recommends connecting with as many people as possible - he has 2,300-plus connections, uses them to find info on whatever he is working on at the time.
He likes the birthday function in Facebook, finds that people really like being greeted on their birthday.
He says you'll think Twitter is stupid until you use it for a while, then you'll start finding it indispensable. I'm still at "think it's stupid," but I'm trying to keep an open mind, since there are people whose opinions I respect who swear by it. (Also swear AT it for frequent server oopsies.)
He uses a widget called Lijit to aggregate all of his social media incarnations on his blog at chrisbrogan.com. He's on MyBlogLog, Small Boxes, del.icio.us, Digg, YouTube, Reddit and others. It's so meta -- he has a network of his networks.
I see potential value in all of these tools - but how do you find the time to use them effectively? They all have their quirks and their learning curves - I can't imagine playing in as many sandboxes as Chris does.