User-generated content can come from anywhere around the world and at any time. As your site or app grows, you might experience more user-generated content submitted than it's feasible for any single person to review.
Here are some suggested strategies and solutions:
Create different levels of trusted users
For new users who don’t have a history on the site or app, review their submissions before allowing them to appear. As users prove their trustworthiness, increase the trust that you extend to them by allowing their posts to appear.
For a variation of this, limit the types of content non-trusted users can submit; e.g. allow text but not images or links.
As your site or app grows, a community will develop around it. This community, because they use your site or app, wants to see your site or app flourish. Recruit user-moderators to review content and help you maintain a high standard of community discourse.
You can also consider employing human content reviewers or moderators to review the user-generated content on your site or app.
Use third-party tools or plug-ins for commenting
Instead of building your own in-house commenting system, you can use popular third-party tools or plug-ins to run commenting for you. Many of these systems have robust moderation and content filtering built-in.