Saw a couple of articles here in Australia and also on web about 'No e-mail days'.
Intel joins many other companies that has announced a weekly no-emails day for some engineers.
If you read the above article, you would see how some research work proved that too much emails are lessening workplace productivity.
However, I think this depends on the area of work for each employee. In the context of IT industry, technical resources need not use extensive amounts of emails, but there are other areas of work where emails are hard to avoid. It depends on circumstances as well, sometimes, emails serve the purpose of official approval/documentation, which would be much quicker than producing a document.
If a phone call or just a casual face-to-face chat is quicker and good enough, no reason to waist time on an email.
Another side of this is to have only the relevant people on email recipients lists. Copying irrelevant people just wastes valuable time of those people.
So, it's all about judging and choosing the best communication method for the purpose.
These days, I am having a really busy time at work and receive about 100 emails a day and send over 50 on most days! In hindsight, its near impossible do without sending and receiving that much....this is after using the phone and direct communication as much as possible...it's just the way it is...