[cptskippy]

    90% of the users signed up without announcing it formally

Considering you can automatically provision accounts and get 100% signup, that's a pretty low number.

They rolled it out at my organization and everyone was automatically signed up and receiving notifications. We put together instructions for deleting your account and passed it around because that was the only way to get out of notifications.

Even still our communications department tried to push it as the primary platform to disseminate information and it was pretty worthless. It was destroyed in the annual survey they sent out and quickly faded into obscurity.

I guess it just depends on how you roll it out. I personally don't see the value in a social network for the office unless you're trying to identify who wastes time in the office not being productive.

[Spooky23]

We used the standalone free Yammer that requires opt-in.