The Collaboration tab lets you view, manage, and invite contributors for your search engine. The page shows you who is already contributing to your search engine, who has volunteered to contribute, and who you have invited to contribute. It also allows you to send invitations to people to contribute to your search engine. In the Basics tab, you can specify whether you want to allow people to volunteer to contribute, or only allow people that you invite to contribute. If you allow people to volunteer, the Collaboration tab will show you information about who has volunteered and you can accept or reject them as contributors.