Users that register to the site are identified by their chosen username. Users select a password, which is confidential and used to verify the integrity of their account. Except insofar as it may be required by law, no person should disclose, or knowingly expose, either user passwords and/or cookies generated to identify a user. Once created, user accounts will not be removed.
Edits or other contributions are generally retained forever. Removing text from a page does not permanently delete it. Normally, anyone can look at a previous version of a page and see what was there. Even if a page is "deleted", a user entrusted with higher level of access may still see what was removed from public view. Information can be permanently deleted by individuals with access to the server, but there is no guarantee any permanent deletion will happen.
User contributions are aggregated and publicly available. User contributions are aggregated according to their registration and login status. Data on user contributions, such as the times at which users edited and the number of edits they have made, are publicly available via user contributions lists, and in aggregated forms published by other users.
No more information on users and other visitors reading pages is collected than is typically collected in server logs by web sites. Aside from the above raw log data collected for general purposes, page visits do not expose a visitor's identity publicly. Sampled raw log data may include the IP address of any user, but it is not reproduced publicly.