Quote:
Ownership of Data: Title to, and all Intellectual Property Rights in, the Data remain Your property. However, Your access to the Data is contingent on full payment of the Xero Access Fee when due. You grant Xero a licence to use, copy, transmit, store, and back-up Your information and Data for the purposes of enabling You to access and use the Services and for any other purpose related to provision of services to You.
My reading of that is they aren't allowed to aggregate your data with others and provide to others. The initial roll out will not provide comparison to others (this is confirmed on their blog). My guess is they will either update their T&C or comparisons will be opt in, in which case you will only be able to compare to others that have also opted in (or they may do opt out if you don't want your data).