Bubbly introduces instant chat for agents, allowing your agents to get instant answers/results from other agents. Bubbly is located within the Zendesk agent portal and more tightly integrated with Zendesk than any 3rd party chat systems can provide. And it's free!
When an agent posts a chat message, all of the other agents will receive the message. If an agent doesn't have the Bubbly chat panel open, they will see a notification on the Bubbly icon informing them of how many new messages have arrived. When an agent is mentioned in a chat message they will receive the standard Zendesk pop-up notification displaying the message to them.
Bubbly is perfect for making general annoucements to all agents, for crowd sourcing answers amongst agents, and for adding some light hearted discussion to the day (depending on your company's policy regarding fun).