Some of Wikipedia's pages on anonymity:

General links:

• Wikipedia:Changing attribution for an edit (not functional since early 2005; see Bugzilla #3539 for an automated idea)

Privacy policy

See Wikipedia:Privacy policy, Wikipedia talk:Privacy policy, and m:Talk:Privacy policy

This is "an official policy approved by the Wikimedia Foundation Board of Trustees. This policy may not be circumvented, eroded, or ignored on local Wikimedia projects."

Summary: If you only read the Wikimedia project websites, no more information is collected than is typically collected in server logs by web sites in general. If you contribute to the Wikimedia projects, you are publishing every word you post publicly. If you write something, assume that it will be retained forever. This includes articles, user pages and talk pages. Some limited exceptions are described in the main policy.

Blacklists

Currently, people using open proxies or otherwise on the SORBS blacklist can't create accounts or log in.

Checkuser Policy

• See the m:CheckUser Policy/Wikipedia:Requests for CheckUser

See also: Editor's index: privacy

Guidelines related to anonymity and pseudonymity:

• Wikipedia:Username policy
• Wikipedia:Changing username
• Wikipedia:Courtesy vanishing and m:Right to vanish

• Wikipedia:Wikipedia is anonymous
• Wikipedia:Welcome anonymous editing
• Wikipedia:IPs are human too
• Wikipedia:IP addresses are not people
• Wikipedia:The overuse of anonymity at Wikipedia and a proposal
• Wikipedia:How to not get outed on Wikipedia
• It's better to remain anonymous

Research

• Anonymity and conformity over the net
• Anonymity and Peer Production

Rejected guidelines

• Wikipedia:Accountability
• Wikipedia:Editors should be logged in users
• Wikipedia:Disabling edits by unregistered users and stricter registration requirement

At some point in 2003, there were role accounts on en:wp and on fr:wp. As of late 2005, they became considered harmful, and were discontinued by policy on most wikis.

• Bugzilla #550 – blocking IPs without affecting formerly-created accounts (long discussion; should be combined with a throttle on # of account creations per IP per [day])
• Bugzilla #53069 Mobile editing requires sign up/log in. Readers cannot edit on mobile anonymously. See mw:Extension:MobileFrontend and m:Research:Anonymous mobile editing in Italian Wikipedia (as of 15 Nov 2014)