I just tried Makemake.io, it's pretty neat. One thing I'd really like with it, is to be able to save on my hard drive the page I just made, so I could use integrate it with my own website not hosted as your subdomain.
I'll have to take a look at adding that feature! In the meantime, you could consider iframing the site. I know this isn't ideal, but it might work depending on your use case.
Well, I still can save the webpage under my_webpage.makemake.io and then save the source, but it's not so convenient.
What you could also do is integrate makemake.io with a subversion, so as a user I could change my website, and then compare it with a previous version.
Anyway, keep up the good work!