Any site accepting user input, comments, profiles, forums, uploads, will attract spam. Google holds the site owner responsible for what appears on the domain.
Prevention
- Moderate contributions, or require approval for first posts.
- Add
rel="ugc"oderrel="nofollow"to user-submitted links. - Use CAPTCHA or equivalent on submission forms.
- Block known spam patterns and rate-limit posting.
- Turn off comments on old posts that no longer receive genuine discussion.
Signs of a compromise
Unexpected pages in site: results, sudden index growth, security warnings in Search Console, unfamiliar redirects for mobile visitors only, or content visible to Googlebot but not to you, cloaked injections are common.
Alien Road recommends: search your own domain monthly for pharmaceutical and gambling terms. A hacked site is usually discovered by the owner weeks after Google found it, and that gap is where the ranking damage happens. A two-minute check catches it early.