Team communication for the 21st century. Slack is a free tool that eliminates the need for internal emails. It includes features such as group and private messaging, inline images and videos, rich link summaries, and notifications.
Teams of any size, it allows for meeting reduction, internal e-mail reduction and increased productivity. Enterprise version not available yet.
Customer stories: https://slack.com/customers
Create a team (sign in, set name of the team, create slack team domain), send invitations and start sending messages.
3. Idea generation, collection and evaluation.
None, but it is not available for enterprises.
Slack integrates with Twitter, Dropbox, and Google Drive, and automatically syncs between your computer, smartphone, and tablet.