I am not a fan of current e-mail offerings. It is full of Spam, Viruses, Worms and Phishing and the messages capacity is permanently growing.
Some of the limitations should and could overcome by technical improvements by e-mail vendors and by different approaches by Internet Service Providers (ISPs). For example, ISPs can eliminate messages including Viruses, Worms or Phising with no additional charge.
Other limitations are inherent. For example, Spam filtering by Anti-Spam is done by usage of statistical indicators and will never be 100% accurate. In an article I wrote few years ago, I pointed at the similarity between Signal Detection theory and Spam filtering: both are based on statistics (usually on Bayesian algorithms) and assign different weights to different error types.
Despite of my opinion on e-mail technology when I was asked for my opinion on the question appearing in this post's title, my opinion is that Google Wave will not make e-mail obsolete.
Google Wave is very creative and could have some advantages over e-mail. However, I do not think this application or other similar application will make e-mail obsolete, same as e-mail did not make mail obsolete or Instant Messaging did not make e-mail obsolete. For certain tasks, mainly collaborative mailing, it may replace e-mail, but for one to one communication traditional e-mail will be used despite its limitations.
e-mail vs. Google Wave is similar to Word Processor vs. Wikis. Wikis did not replace Word Processor but are better fit for collaborative documents. Although, I do not think Google Wave will replace e-mail it may improve it significantly. The future e-mail may include some of Google Wave ideas, such as single copy of messages.
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