Interesting discussion here, to which I was recently sent a link to by the folks at ITinCanada.ca.
One thing I find quite interesting here is the seemingly polar opinions about controlling or not permitting employees to use social media, vs. allowing it because it is for personal use.
Perhaps you are familiar with IBM's approach to this, which has been fairly broadly lauded... ultimately, participation in social media (both outside and inside the firewall) is permitted and encouraged, within the constraints of the IBM Business Conduct Guidelines
that each IBMer must agree to on an annual basis (after taking an online course that highlights changes and key components of the BCGs).
IBM's Social Computing Guidelines
are an addendum to the BCGs, and highlight specific behaviours that are encouraged / not permitted... around specific risks for IBM, such as reputation, intellectual capital, liability, etc. As an IBMer it is clear what I can and can't do, and where I can and can't do it - and it applies equally to a coffee shop, in an email, on the phone or via social media.
Regarding the specific value of microblogging inside the enterprise: Interestingly enough, when this discussion started nine months ago, I would likely have had a similar opinion - that microblogging has little value to the average employee, and should be controlled, but as I have seen it evolve and begun to use it myself, I now find tremendous value in our internal microblogging tool. Of note, though, is that IBM's internal platform does not fall into the stand-alone category. While stand-alone from the public internet (i.e. Twitter) it is highly integrated into the other collaborative and knowledge systems in IBM, so when enhanced with updates on recent activity for those in my network, the value it brings is tremendous. Quantifying that value is, as with so many things in this domain, a challenge. I would put it into the "keeping me in the loop" value bucket for the most part, except when I have a specific urgent need/request for information or perspective from my peers, and at that point, I can easily say that internal microblogging has saved me on the order of days of effort in 2010 alone.
Personal Disclaimer: The postings on this site are my own and don't necessarily represent IBM's positions, strategies or opinions.