"Finally, in looking at the evolving style of communication inside of a little place like JotSpot, we use e-mail for urgency. So we use the blog for highlighting, the wiki as the repository, and e-mail to convey urgent messages....
It's interesting to note in one small environment the balance between e-mail, instant messaging, blogging, and wikis. What we're seeing is that each serves a purpose. We're one of those places where I'll instant-message someone sitting no farther away from me than you are now—to send a quick note in a point-to-point way that needs to be handled immediately.
I rarely IM programmers, though: The most important thing in programming is to let them to stay in the flow state. This means that the most productive thing most people can do is actually turn off their IM client. So we're pretty judicious about IM use. I tend to e-mail questions to engineers because I don't want to interrupt them. How can you not use e-mail? We actually use very little e-mail internally, but you've got to use it for stuff externally...
I really believe that JotSpot's mission over time is to transform web-based applications the way that Excel has transformed financial apps. We want to enable end-users to build these ad hoc, one-time-if-necessary web-based apps. And we want to enable a lighter-weight class of programmers to do a lot more than they ever could before."
(JotSpot founder and CEO Joe Kraus, Wikis and Blogs and E-Mail, Oh My! :: Always On)