Update: Actually, the folks at Yammer, Socialcast, ESME, and other "Twitter-like" enterprise vendors or open source efforts should all address these issues...add comments and I'll aggregate them into a summary post.
I think it would be very helpful if the Socialtext folks could explicitly answer how Signals supports enterprise requirements for security, access controls, archive/logging (for audit, compliance, and records management), directory integration, and policy management overall (individuals, groups/roles). It would also be helpful if integration with IM/presence could be clarified in regards to a roadmap. This information should be made very visible as it is either a source of competitive differential, or an unfortunate gap.
Without this type of information (despite the well-deserved media coverage), I'm afraid the product will be virtually dead-on-arrival for most organizations that have these requirements for other messaging/communication systems - they apply to these tools, regardless of what we call them (i.e., micro-blogging).
Background from my earlier posts:
Socialtext Releases Signals Micro-blogging Application for the Enterprise
Twitter-style Application Expands Socialtext's Enterprise Collaboration Platform with Secure Social Messaging Application -- Socialtext Desktop Public Beta, Powered By Adobe AIR
Palo Alto, CA - March 3, 2009 - Socialtext, the leading provider of Enterprise 2.0 Solutions, today announced general availability of Socialtext Signals™, the Twitter-style social messaging interface for the Socialtext platform. Socialtext Signals provides customers simple and efficient information sharing capabilities, and further expands the company's enterprise social networking and collaboration platform. Socialtext also announced the public beta availability of the Socialtext Desktop, a rich desktop application powered by Adobe® AIR®, for monitoring and participating in social networking, collaboration and social messaging.