Bring your own software
Everyone has their favourite software. Each department has their own tools. Sometimes we need to share things with each other, and we can't always share access or train staff on new tools. Igloo allows you to bring in other cloud and web services, like SharePoint or SalesForce, to share content with team members in the same place you're talking about it.
And because you can upload any document type, you still have full version control, commenting and related objects, regardless of if it's a Word document, a Photoshop file, or a block of code.