By default, users come in at Level 0 and become upgraded over time based on what they do, to Level 1, 2 and 3. At each Level, you can do the things at the earlier Level plus what you get at the new Level.
Whether accidentally, or intentionally, new users can cause problems in a community. We also want to hide any so-called "advanced" functionality from new users to make the UI less confusing for them and gently land them on the deeper UI as they get more experienced.
Users at Level 0 cannot:
• Send private messages to other users
• Flag posts
• Post more than 1 image
• Post any attachments
• Post more than 2 hyperlinks in a post
• Have actual links in the 'about me' field of their profile (will be silently and temporarily converted to plain text)
• Mention more than 2 users in a post
Users can get to Level 1 by:
• replying to at least 1 topic
• reading at least 5 posts
• spend a total of 5 minutes reading posts
Users at trust level 1 can:
• Upload images & attachments
• edit wiki posts
• flag posts
Users can get to Level 2 by:
• visiting at least 15 days, not sequentially
• casting at least 1 like
• receiving at least 1 like
• replying to at least 3 different topics
• entering at least 20 topics
• reading at least 100 posts
• spend a total of 60 minutes reading posts
Users at Level 2 can...
• Use the "Invite others to this topic" button for one-click onboarding of new users to participate in topics
• Invite outside users to PMs making a group PM
• Daily like limit increased by 1.5×
These are the most active readers and reliable contributors over long periods of time. Unlike the previous levels, this is upgrade is time constrained. To get to Level 3, users must do the following within the last 100 days:
• visit in at least 50% of days
• reply to at least 10 different topics
• of topics created in the last 100 days, must have viewed 25%
• of posts created in the last 100 days, must have read 25%
• receive 20 likes, and give 30 likes.*
• not receive more than 5 spam or offensive flags (with unique posts and unique users for each, confirmed by a moderator)
• not be suspended
These likes must be across a minimum number of different users (1/5 the number), across a minimum number of different days (1/4 the number). Likes cannot be from PMs.
All of these must be true.
Unlike other trust levels, you can lose trust level 3 status. If you dip below these requirements, whether from flagging or the passage of time, you will be demoted to Level 2. However, in order to avoid constant promotion/demotion situations, there is a 2-week grace period immediately after gaining Trust Level 3 during which you will not be demoted.
Users at trust level 3 can:
• recategorize and rename topics
• access a private "frequent flier's lounge" category only visible to users at trust level 3 and higher
• have all their links followed (we remove automatic nofollow685)
• spam flags cast on TL0 user posts immediately hide the post
• flags cast on TL0 user posts in sufficient diversity will auto-block the user and hide all their posts
• make their own posts wiki (that is, editable by any TL1+ users)
• Daily like limit increased by 2×