Please have a look at my stats. http://secretipaddress.com/stats/index.php?mode=stats&sid=431797&show=latest&lang=en All the visitors from the pron sites are from a single IP or the same visitor. Can somebody confirm if there is really a link to my site on theirs or this some kind of promotion for their sites. should I block that ip?
It's called website statistics spam. People see those URL in their statistics, and they click the links to see if there is a link on that page, and when you will go there you will see nothing but porn. It's a method of promoting (spamoting) your website traffic. Used by porn webmasters, just ignore those links and they will stop after a couple of weeks, happened to me once. Dont worry.
I had the exact same problem with the same sites. Put a password on your stats directory and it will go away.