In general, what is the legality of website forking?
I am based in the United Kingdom and intending to host my website on U.S. or Canadian servers.
I am looking at creating a website about automobiles (with original MSRPs and specs) that is a sort of fork of http://www.autos.ca or http://www.parkers.co.uk in terms of design, but not content (the site would be less news-driven, more original research and automobile history-based).
I also have a small project for an online radio station, maintaining the site every so often - it's a WordPress site, I manage it but have no access to the Apache/Linux side, and they want to go to a design more like http://www.pulse1.co.uk but how would you fork the design for a PHP-based site (Pulse 1 does not use PHP, according to BuiltWith) and avoid copyright infringement?
I know that software can be forked, but how often is website forking done, and what do I need to do to keep it compliant, and avoid copyright infringement (even though I am not copying from the original sites, and all content is my own original research, apart from the images).
If anyone could advise me, I would appreciate the advice.