I am building a site with a GNU licensed program called OpenCart.
Now I am not “distributing” anything.. but people can see my website and interact with it.
Generally I avoid GNU like the plague as an app developer. No way my customers want their hard earned work set out to be free. In this case all I am doing is filling and maybe writing a few custom pages. This is such a scarily worded license. What extent is liable under it? I have the site, but will people have the rights to my photos, IP, and widgets / applets I write for use on my site?
If you use GPL licensed components in your program or website, then the requirement that the GPL places on you is that if you give/sell the program/website to someone else, then you must also give them the rights and means to create derived versions of the program/website.
Allowing people to access your website over the internet does not mean you have given away your site’s code, so the GPL does not place any requirements on you.
Also, using a GPL program to create creative stuff (like images, software, written text, etc.) does not affect in any way what you can do with your work. You certainly don’t have to give it away for free.
You can only claim copyright protection on something if the end result contains something that is the result of your creative effort. If you use a tool to create something, then in almost all cases the work you created will not have any trace of creative effort from the side of the tool authors. Therefor, the tool authors don’t have any copyright claim on the work you created.
The most notable exception here are tools that generate complex programs from simple descriptions, like parser generators. There it is entirely possible that the output contains the results of creative effort from the tool authors. For normal editors and even compilers that is not the case.