According to the Customer Agreement and Your Data section, "you hereby grant to Atlassian a non-exclusive, worldwide, royalty-free right to (a) collect, use, copy, store, transmit, modify and create derivative works of Your Data".
Our organization has confidential data that it does NOT want to share with Atlassian. It seems that a self-host instance is one way to keep Your Data private. Does the Customer Agreement apply when Confluence is self-hosted?