An interesting aspect of online group communication is the phenomena of backchannel. Backchannel in computer-mediated communication (CMC) allows participants within a group conversation to exchange private communication which is visible only to the sender and receiver. Many existing forms of CMC provide such capability – think IRC, Skype and even Twitter (through direct messages).

Launched 5 months ago Subtextual (until recently, known as bccthis) is an interesting plug-in for Microsoft Outlook that allows the mixing of public (visible to all recipients) and private (visible only to specific recipients) content within a single email message. This allows a sender to send a single message, but add private context addressed to only those people that need it.

Subtextual adds the ability to send a hidden message as part of a normal email message. This hidden content is visible only to selected message recipients – other recipients never see any indication that the message has any additional content. Happily, recipients don’t need any plug-in to view Subtextual messages.

As well as the Outlook plugin, Subtextual also have a Twitter client (which seems less compelling to me), a FireFox plug-in for using Subtextual with Gmail and a BlackBerry application.

While clearly an interesting idea, I’m not sure whether Subtextual, is significant enough to be more than just another feature for Outlook. I am, however, impressed with their family of products across desktop, mobile and web-based email. Together with their recently announced premium version of the Outlook plug-in, it feels like the company is busy experimenting, trying to discover the platforms which can deliver them traction, customers and revenue. I am very interested to see in which direction this company will pivot in the future.

In work reminiscent of their original ReMail work, but targeted at mobile email, IBM is rethinking mobile email. Their focus is on fast email triage on mobile devices, including how to capture intended actions, such as those that might be actioned on the desktop at a later time (rather than on the mobile device).

While it’s widely acknowledged that desktop email clients have been slow to adapt to changing volumes and styles of email use, the problem is arguably more acute in the mobile space. For starters, obviously the device form factors influence how people use mobile email – you’re not likely to see people typing long-winded messages with their thumbs – yet many mobile email clients are essentially designed as smaller versions of desktop email clients. Mobile email users typically focus on triaging their messages to determine what’s new, what they can delete right away, and what’s important enough to handle immediately. They often defer everything else until they are at a desktop or laptop with a full keyboard and larger display.

I think it’s worth spending 7 minutes or so to watch the video below, where Jeff Pierce outlines the project:

There’s more information, including a short paper, also available at the Triage and Capture: Rethinking Mobile Email website.