The WSJ is making the call—email isn't as important as social networks. It's an interesting conclusion, derived from the fact that both growth and absolute numbers are on the side of social networking this year. That's kind of weird.
You might someday send resumes or other important documents over Facebook and Twitter, but Email is never going to be "dead". In fact, with push email on your phone, it's basically as instant as any of the other networks.
Google Wave might also be pretty interesting when the people pimping it out call it what email would look like if it were invented today. It's too early to tell. But for it to be truly ubiquitous—and it has to be in order to replace email—it can't be hosted by just one company.
Think of it this way: if people are still using Fax machines—fucking FAX MACHINES—on a daily basis, there's no way that Email will be excised from our collective productivity streams. Not when it's this much more usable by the average person than faxes.
Lastly, how did they come up with the number of social network subscriptions being higher than email, when all social networks require you to sign up with an email account? [WSJ]