Q:

CKEditor usage in commercial used website

Yes, i have seen this question before, but i have never found a clear answer, so i'll try it again.
I'll explain below why i don't have an answer yet.
Can i use the CKeditor for free at the site i'm building.
This site is an open website, available for everyone to register, built by me, for a third party.
If you want to compare it to something else on the web: i am building facebook for the facebook guys. The facebook site is open for everyone, and they are making a profit of it.
Now i've (tried to) read the licences for the CKEditor, but they all seem to care about me modifying the source code, and wether i'm redistributing souce code, and if i make my modifications on the source code public available etc. etc.
The point is: i don't care about the source code. If i use the facebook example: if i use a html editor in the facebook site i'm building so members can use html in their profile descriptin, i don't care about the source code of the html editor, i'm not distributing the source code, i'm not redistributing the source code, i' not editing the source code etc., i only use the control in the facebook site hence i deploy the binaries to the server and nothing more.
If i can make one more compare: i use it like i use all the .Net binaries: deploy it tto the server, members 'use' the code in the binaries because my code makes use of the binaries, but nothing more, and the source code gets untouched.
Also, i am not planning to redistribute the .Net binaries, extend them, make them available for others.. the same is true for the usage of the CKEditor.
I did read there is also a commercial licence, which is 'copyleft'. I don't know what they are talking about, i have never seen 'copyleft' on my VS2010, Word, Avast, Resharper etc. licence.
Can anyone give me a clue?
EDIT: i think you can compare it to the Jquery usage also.
I use Jquery on my site, but only use the binaries (so to speak) as is.

A:

There are three Copyleft licenses for CKEditor as of now. They are 

GPL
LGPL
MPL

GNU definition of CopyLeft license states

Copyleft is a general method for making a program (or other work) free, and requiring all modified and extended versions of the program to be free as well.

Which essentially means you cannot edit source of CKEditor and then pawn it off as your own for a price. You are bound to re-distribute it for free forever that way; regardless of how much you have changed the original source code.
From what I read from your post, I would dare say you can surely use CKEditor's free version in your site.

