This simple intervention is a message to new users of a platform or new members of an online community that contains three key elements:

1. A link to what is considered trolling in the community or platform
2. A warning that users will sometimes see trolling, but that non-trolls outnumber the trolls
3. Instructions for how to handle trolls

This can appear as an automated comment to a new user's post, as an automated personal message, or as an interstitial upon entry.

This intervention has been shown to:

1. Increase retention of users who join the community in good faith. Those who know beforehand that trolls are present and have the tools to deal with them are less likely to be scared away from the platform by harassment (CAT Lab, 2020).

1. Increase proportion of good-faith users relative to those who join as provocateurs. The increase in retention was limited to those who actively identified with the mission of the community - retention did not increase among those revealed not to be joining in good faith (CAT Lab, 2020).

CAT Lab (2020) conducted a two-year project with r/feminism on Reddit to test an idea for reducing harassment. After presenting 1,300 users with the intervention, they found that messages explaining that harassers were a minority increased newcomer comments by 20%. This effect persisted across the full 10-week period of the experiment.

This intervention could be useful for reassuring and empowering marginalized voices who would otherwise be silenced by hostility. It may also help with polarization as it enables newcomers and outsiders of an online community to more accurately gauge hostile users as being the minority that they are, rather than seeing them as representative of the entire community and treating that community accordingly.