First of all I can assure you all the data this process sends serves only for statistical purposes. It never sends any user's data, and nothing what would uncover user's real identity.
The process sends some data when something important happens (e.g. update/install/uninstall/repair). When participation in the community is disabled, it only adds program and virus definition version and some event specific data (e.g. what avast component required repair).
If the participation is enabled, it sends few more data about the machine like Mac OS X version, system uptime, user's locale, user ID (number only), kernel arch (32bit or 64bit) and similar data.
Regards,
Mity