Lookit, a micros~1 advertorial.
There's these hippies Out There that've been doing much the same thing in mailing lists, usenet, using irc, what-have-you. Yes, wikis too. IM systems not so much as you usually need to talk to multiple people.
Twitter isn't special and worse, much harder to control, as in once posted you can't un-publish the them. They're in somebody else's database even if you remove them, and who wants to put his great ideas right on the public internet for all to see?
Much better to keep that sort of thing in your own hands. Plenty of tech-driven companies do, and run their own mailinglist software, their own news server, their own irc server, their own wiki or blogsite, all internal. The key is never the technology, but always to find something that fits the workflows of the team or company and then get people to use the tool to good effect. It matters very little what it is, as long as people do use it.
micros~1 hasn't set much of a standard in any of that. It never fails to puzzle why people think they're great at management, as (per Drucker) the only place to see and measure the results of management is outside the company. And looking at what they produce, er, it's not pretty.