I actually clicked on an ad.
It's a way to share things and collaborate in the social style of Facebook, Twitter, Google Drive and more -- without the messiness of trying to do this in any kind of private or semi-private way on a wide-open social network.
Here's Igloo's less-than-50-word description:
Igloo is a modern intranet. It helps you work better with other people by keeping your content and conversations in one place. (It's also hosted and managed, so you can focus on your work, not your IT budget)
I know little more beyond what's on the page linked above, but I do know that for small businesses it's free for up to 10 users, and per user after that.
In terms of apps, here's what the Kitchener, Canada-based Igloo says about itself:
Every digital workplace includes team spaces; file sharing and document storage; activity streams; unlimited blogs, microblogs, forums, calendars and wikis; member directories and profiles.
Have you heard about Igloo, or used it? Let me know.