The email client is evolving into an IM client as well
The latest Mozilla Thunderbird has just been released, along with Firefox 11, bringing with it an updated Gecko engine as well as a few changes and enhancements. But the more interesting stuff is happening further upstream.The most recent Earlybird builds, Thunderbird 13, now sport support for instant messaging and chat.
The feature is not yet complete and what is there doesn't always work, but the Chat feature should be more than ready by the time Thunderbird 13 makes it to the stable channel, some 12 weeks from now.
Right now, the Thunderbird Chat feature supports Google, Facebook Twitter and IRC. However, only the Google and IRC modules seem to be working, the other two don't.
Still it's an interesting development for the venerable email client. It will also be an odd choice as a default feature, the first big one in years.
A calendar app, Lightning, has been around for years and, while it's being worked on by the Thunderbird theme, it's still an add-on and not built-in functionality.
Chat is a useful addition to email, the fact that it's built into all of the big webmail clients, Gmail, Yahoo Mail and so on, indicates that the feature is useful to a lot of people.
It certainly can come in handy in a lot of cases, many times an email conversation will degenerate into a pseudo-chat. Real-time availability and the ability to get an answer quickly via chat would cut down on the need to send an email many times.
With volume being one of the biggest if not the biggest problem with email communication, anything that helps drive down the amount of email sent and received every day is a good thing.
Of course, most people that would need this already use either the web version of their favorite email service or use an IM client, or several, alongside Thunderbird. Having more communication options built into the same app, with a unified address book and multiple-account support is a better alternative.