Why porn sites have links to my blog?

Referrer spam mostly unless someone is targeting you (google Negative/black hat SEO).

The best thing to do is to submit to google search console as a "Disavowed back link" [0] which is basically telling google that you don't want these to be counted as backlinks and they will exclude in ranking calculations.

Also, add them to your google analytics as referrer spam [1]

[0] https://support.google.com/webmasters/answer/2648487?hl=en

[1] https://support.google.com/analytics/answer/1034842?hl=en

Could it be your domain was previously owned by someone that had a high SEO score? Were you the first to ever register that domain? The wayback machine can help answer that. [1]

If you want to have some fun you can redirect requests based on the referrer to a site of your choice. Or maybe just create a blog entry on your site about referrer spam, your thoughts on porn sites, etc...

[1] - https://archive.org/web/

Here how I always thought that worked:

- They know webmasters will go through their referrer log, and when they see the link they'll click through to see who's linking to them. (Hence visiting their site.) It doesn't cost them anything -- and if they do it enough times, they'll actually get something like traffic.

- Also, some blogs use a plugin that automatically detects when a site has linked to a post -- and then announce that (in the form of a comment on that post).

referrer spam