When emails are seen in seconds and minutes, and response times (expected and real) are in seconds and minutes, has email become real-time enough to substitute for instant messaging and chat?

In most places, email remains the channel for formal communication because there are persistent records, some threading of conversation, and the tempo is slow. But in some places, especially BlackBerried teams, people expect sub-minute responses to inter-office email. This tempo is comparable to casual chat over IM. Beyond tempo...

Email is starting to offer presence!

Now that Google, AOL, and Yahoo! are blending IM into their webmail services, you should be able to tell if someone is getting your message right now. You still won't know is if it was lost in a massive inbox or misfiled in a spam bucket. And it won't apply to people outside your hosted mail service. But it works and will increase its reach.

So email is starting to look a lot like IM for millions of people.

Email as IM brings us back to Microsoft's four ways of thinking about VoIM (voice over instant messaging). As part of:

1. The portal lifestyle, along with blogs and shopping.

2. A Unified Communications system that brings IM and VoIP into the world of Outlook and Exchange and Microsoft Office.

3. The Windows platform, just a feature for Microsoft's millions of programmers to build into their own software.

4. A bizdev gambit.

The Portal Lifestyle meme is Lively, Fun, for Consumers and Tweens. Parental controls, avatars, skins, and MySpace buttons. XBox360 with Messenger inside. VoIM wearing Adidas. The MSN/Live advantage is huge; blending Messenger into online properties is not only cheap marketing for Messenger, it can add value to existing properties. Microsoft's blogging platform is one of the world's largest. So are its email service, its shopping networks, its search and mapping engines. VoIM adds a real-time social element to its services. Is online dating better if you can chat with a prospective date? A prospective employer? Voice and Video over IM are the new "sticky factor" for web businesses.

The Unified Communications meme is full of knowledge management jargon coated in a hard security shell. A perfect confection for IT operations. VoIM is merely one more communication mode to be plugged into access controls, provisioning, server farming, and network monitoring. VoIM in a suit. The current version of Skype for Business is a lifestyle product putting on that suit and on its best behavior. Can Skype integrate too aggressively with the Microsoft communications, office, and business suites?

The Component meme may endure. I haven't seen a strong set of VoIM elements built into Vista or Microsoft's development tools. I'm sure they're coming. When they do, anyone with a junior high school programming background will be able to build their own "Skype" desktop, web, Zune, or mobile client in a few hours. What happens when most of the technology becomes cheap/free/open and designs become conventional (think rotary or dial pad on phones)? The basis for competing shifts to value-added services and social capital lock-in. Value-added services like trusted ways to pay and get paid, like Skype Prime. Social capital lock-in happens when it is more costly to abandon your hard-won buddy list if you switch to another network.

The bizdev playing card. The fourth meme, dark and quietly simmering, positions the whole VoIM thing as bait. As Microsoft allies with telco and cableco partners around the world, Messenger's large VoIM userbase and database (spelled "sales prospects") has value. How long before Vista ships with an AT&T-powered MessengerOut? Don't discount VoIM's role in Microsoft's business development.

Back to email. And Skype.

I asked Should Skype offer email? skypename@Skype.com? in February. Now more than ever.

• I think it plays in all four memes.
• @Skype would let users create one inbox and history file with multiple views for all communication modes.
• @Skype APIs would let developers mash-up Skype in new and useful ways.
• @Skype would spread the word about Skype faster and to more communities than the existing Skype network.
• @Skype would let people choose more communication modes so they spend more time in Skypeland.

Email has its own design, operational, and economic problems, so entry isn't cheap or easy. But what happens when all the other VoIM players are well and closely tied to email? And Skype isn't?

See also:

• Could Skype achieve Windows-like lock-in?
• Dear Michigan Telcos - Part 4. Skype helps relationships more than you do
• Voice 2.0 - It's About Building Unique Communities
• Skype Is ... "Open for Business"
• Walking through Skype Prime Beta