I'm pretty sure there were some that said this sort of thing couldn't be done - run an intranet on an enterprise microblogging, cloud-based platform like Salesforce Chatter. But a few weeks ago - the concept we heard about last year - went live at Virgin America:
The encouraging thing here is that, Appirio, the site's developer:
"helped guide Virgin America away from making merely cosmetic tweaks to the existing Chatter experience and towards the development of a new application built on the Chatter API and hosted on the Force.com platform-as-a-service (PaaS)."
This isn't the first time we've seen the API of an an enterprise microblogging utilised to create a unique solution (e.g. Nokia Socializer) and I hope we see more examples like this in the future.