A recent Wall Street Journal article noted (pay link) the rise of alternatives to email. The article itself is balanced and mentions that new ways of communicating are likely to just add to how much time we spend with this stuff, not replace email and cure its problems. Whether that's good or bad depends on what you're communicating, I guess.
The article inspired a number of posts about the death of email, misunderstanding the article, but providing some interesting info. Here's a few of them. Both The End of Email Predicted, Wrong as Usual, from emailserviceguide.com, and Why Twitter and Facebook Will Never Kill E-mail from the technomix blog at FastCompany.com make some good points about some uses for which emerging 'cloud' services are just not as good as email. They mostly focus on business, which makes sense. You probably don't want another company between you and your customers or partners. Imagine if you could only hold meetings at Starbucks - hit or miss, right?
Rackspace.com's email hosting blog gives us some data in a post entitled "Is Email dead?" short answer - no. It's getting bigger.
And surprisingly, there were a good number of lucid and interesting comments in the slashdot thread about the article. Provided you filter out comments with a score of 3 and lower...