Originally posted by Steam Support:

General Rules

Do not do any of the following:

• Flame or insult other members.
  
• Bypass any filters.
  
• Abuse or encourage abuse of the Post Reporting System.
  
• Post personally identifiable information. (i.e. name, address, email, phone number, etc.)
  
• Bump threads.
  
• Derail a thread's topic.
  
• Post links to phishing sites.
  
• Post spam (i.e. +1, 10char, rickrolls) or Re-post Closed, Modified, Deleted Content.
  
• Repetitively post in the incorrect forum. (example: trade requests belong in trading forum)
  
• Openly argue with a moderator.
  
• Artificially manipulate the User Review system or voting/rating systems.

Content Rules

Do not post any content on Steam containing the following:

• Porn, inappropriate or offensive content, warez or leaked content or anything else not safe for work.
  
• Discussion of piracy including, but not limited to:

1. Cracks.
   
2. Key generators.
   
3. Console emulators.

• Cheating, hacking, game exploits.
  
• Threats of violence or harassment, even as a joke.
  
• Posted copyright material such as magazine scans.
  
• Soliciting, begging, auctioning, raffling, selling, advertising, referrals.
  
• Racism, discrimination.
  
• Abusive language, including swearing.
  
• Drugs and alcohol.
  
• Religious, political, and other “prone to huge arguments” threads.

No Backseat Moderating

Let the moderators do the moderating. Backseat moderating is when people who are not moderators try to enforce the forum rules. If you see a person breaking the rules, take advantage of the Report (🏳) button or simply ignore the offensive post(s), thread, or review.

Report Posts to Moderators

Should you observe a fellow Community member breaking these rules please report the post or item by clicking the Report (🏳) button located on every item, post, and review.

Repeated Offenders

Repeated offenders of the above rules and guidelines will be banned from the Steam Community. Any moderator has the ability to ban a user for violating the rules at their discretion.