[heipei]

I'm facing the same issue with a URL analysis service I operate which lets you take a snapshot and screenshot of a website. I get countless submissions to other sites which allow user-generated content (Reddit, Medium, random support sites, everything that's "open") and all of these sites themselves host images and links to "Watch XX Soccer Game Live 2020 HD" etc., so all link-spam. I found my ways to battle these submissions and users, but obviously don't want to reveal them here.

The other thing is signup-spam. I'd say a full 50% of my signups are spam, and I do my best to remove those user accounts. What surprised me was that the spammers seem to be human, i.e. using a Gmail address (which requires verification), solving Captcha, entering form fields, clicking the email-verify link, etc. Just crazy. Again, the countermeasures are not something I would want to publicize...