There are numerous ways of "stealing" a site - and nothing to really protect them.
Someone can do a copy and paste of the page(s). Easy - anyone can do it. So you get a program that will encrypt the html code...
But, there are numerous "readers" out there that will un-encrypt your site. (And, btw, if they can un-encrypt the site, they can also un-encrypt your codes that are hiding the locations of your ebooks and products for sale!)
There are also site spiders which will crawl your site and download everything
on it - and they will even get all the hidden scripts, etc and duplicate your server directory structure!
With any browser, you can save any webpage to your hard drive - along with the images, etc that go along with it.
And, if all else fails, just use SnagIt to copy the page and then just replicate it with an html editor.
So, what can you do? It's kind of like protecting an ebook from theft - you do what you can, and even if some things like encryption can easily be busted by a hacker, the average person won't know how. And believe me, if a hacker is going to bust you, you cannot stop them.
This person thought they could do a quick "flip" of the site - luckily Gayle found them. It would seem to me that there should be some services that will check for you sites using particular keywords, etc. You can also Google some specific part of your website - a particular word, phrase, title, etc. that should help you find them...
With millions of sites on the Net, the thieves probably feel pretty sure they won't get caught...