I think you just have to live with it. I've never heard of a case where someone copyrighted the structure (rules style or fake blog style) of his website. This would mean pretty much that everyone is infrightining someone's copyright right now..
Yes, you can copyright your text. But if I'm going to rephrase or just give it another twist you can't do nothing about it..
What you can do is use your own images - made by you (which I guess you aren't doing right now, so - yes if that hot milfie that you used for your got 1 cent per view she would be a multi-billionaire) - you can have the copyright of these..
Then I wish you good luck sueing everybody that stole your image..
Or if you are good at coming up with angles and shit, sell them like IamAtilla does with AngleSaurus.
AngleSaurus??
You could never enforce a copyright for a variety of reasons. Unique angles that work can and will be copied quickly.
Landing page is the least important thing to try to improve upon in the adult game. Banners will be copied too but they burn out relatively quickly so you can make a lot of profits and it will be burning out by the time others rip it.
Copyright only protects the exact copy, somebody could rewrite it.
The cost of enforcement will massively, hugely, gigantically outweigh any compensation you get from it.
Don't bother
TL;DR
Focus your effort elsewhere.
You are obviously a very creative individual.
Unfortunately, if your objective is to assert intellectual property claims, I think you are working in the wrong niches within the marketing/advertising ecosystem.
If you apply your skills and start an agency with direct relationships with much larger brand advertisers, you could have much better chance at asserting intellectual property rights.
Otherwise, I think the comments from the others are pretty much spot on.
You have a lot of talent, if you put them to work in the right places, I am sure you can become even more successful than you are now.
Why not come up with more?
In response to copycats, Steve Jobs said that he can invent faster than they can copy
All I have to say is that you're an incredible copywriter and I owe you a lot. It does make me upset that the great ones get no recognition for their innovations in our industry though.
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