I run AbuseIPDB, a free distributed IP threat analysis database that allows users to report abusive IPs (spammers, bruteforcers, etc) through an API, webform, or Fail2Ban integration. We have over 30,000 users and almost 50k IPs reported per day.

I received a legal letter today from Semalt, a company that is probably familiar to many of you as a shady SEO company. They're mad because one of our users flagged one of their IPs on our site with the following comment:

https://www.abuseipdb.com/check/196.216.49.242

"Bot that promotes semalt.com SEO through web log referrer click bait spam with fix-website-errors.com, keywords-monitoring-success.com and keywords-monitoring-your-success.com. Does not identify itself as a bot, nor does it follow robots.txt. Clickbait link includes your domain name to let the bot's master know they got through. Primary site has form to gather domain names."

Semalt says this:

"The above mentioned materials do not contain any truthful information, and you ignore our attempts to clarify the issues related to your abusive comments and articles. You choose to ignore us and continue spreading false information. Our company has never been involved into the distribution of referral spam.

On the contrary, we often suffer from fake referral traffic on our website. The Semalt company has no doubt that you have used the trademark of our company in your publications not by accident but on purpose hoping to attract customers (readers) by using the popular brand/product name. [...]"

Full legal letter is here, including all of the threats of suing for damages, invoking GDPR, etc etc. For what it's worth, they didn't even bother contacting us through the website before sending this.

https://www.scribd.com/document/381802760/Abuseipdb-com-Abuse-Letter

Has anyone else crossed paths with these guys before? It it worth responding to or acting on?

Thanks for your input!