When the "Version Check and Statistics Reporting" flag is enabled (under Global Settings >> Miscellaneous Settings - gather the following information when a version check is done:
CiviCRM version, versions of PHP, MySQL and framework (Drupal/Joomla/standalone), default language, as well as the counts (but no actual data) of the following: contacts, activities, cases, relationships, contributions, contribution pages, contribution products, contribution widgets, discounts, price sets, profiles, events, participants, tell-a-friends, grants, mailings, memberships, memebership blocks, pledges, pledge blocks and active payment processor types.
No information is collected about the organization other than the md5 hash. Since its a url, the IP address is also recorded. When we incorporate long term storage of these logs, we will discard the IP address
No details on contacts (name/email) or contributions (amount etc) are collected. The queries will be a simple count query on some tables (with an optional where clause of is_test = 0)