Some time ago I bought a PHP (crowd sourcing) platform that my entire website is based on and it turned out to be copied from another famous site. I guess some programmer who worked for the original site sold it to me. BTW, I have some papers that they sold me this.

After I bought it I rewrote ~30% of this it, changed the design to customize it for my needs. The site is paid for subscribers and has a good traffic.

I see that the original and mine sites use the same css styles, the same JavaScript libraries.. The layout is similar in some places. Of cause I rewrote something and changed the design/graphic but a professional can compare both sites and find that they are based on the same code.

Is there any way for me to avoid problems?

Is it possible to modify it so nobody can see that these sites are relatives? Like rename css, Javascript libraries?

Are the scripts marked as being copyright?

How can it be marked as copyright?

I asked people who sold it to me and they said that they bought it from the company that developed it for that famous site that I mentioned and then they significantly rewrote it by their own developers.

what should I do?

So the company you bought it from bought it from another company, but the company you bought it from rewrote most of it. From my understanding, if it's legal to resell partially rewritten code, it should be legal to repeat the process. There can't be any copyright on it, otherwise the company that you bought it from could be sued.

Originally Posted by ant1976

How can it be marked as copyright?

By using comments in the scripts and/or code sections that can be activated by a particular page or URI

Originally Posted by ant1976

I asked people who sold it to me and they said that they bought it from the company that developed it for that famous site that I mentioned and then they significantly rewrote it by their own developers.

what should I do?

Ask for written verification of that.

Originally Posted by chrishirst

Ask for written verification of that.

yes, that's a great idea. thank you very much.
how would this written verification would look like?
is this is a just a statement in plain text? Do they have to mention who they bought the script from?

Just something that gives the assurance that they have rights for selling or reselling the script, on headed paper of course.

Originally Posted by chrishirst

Just something that gives the assurance that they have rights for selling or reselling the script, on headed paper of course.

sorry for a stupid question but what is headed paper?

is it not enough just a statement in plain text with names and signatures of buyer and seller?

Headed paper is pre-printed paper with company information and logos etc. It is what is normally used by the company to produce their invoices, quotes, letters to suppliers or customers etc.

By having documentation in such a form can be used to verify that YOU did not simply create the document yourself. And of course by having it posted (mailed) to you, it can remain sealed until such time when, or if you are challenged regarding the origins and/or ownership of the script/application.