Perhaps you have said this elsewhere, but why shut the site down?
* More than anything, I think it's good for things to end! I figured interest in the site would die off over time (and it started to), and I thought it was better to close things out providing a special experience for the people that used it than to keep it up to get a few more users
* Costs started adding up; donations stopped matching them. I coulda figured out how to lower my costs but I wasn't excited about it.
* While the site was up I felt an obligation to make sure someone hadn't found some trivial workaround to deface the thing and I didn't want to do that anymore.
Well done and nice execution.
You know who else said this (in spirit)? Bill Watterson, author of Calvin and Hobbes.
There are few other people I'd be proud to be in the company of :-).