The Bad:The premise of the examples list seems a bit disingenuous.
Very few of these things take into account the full convenience of jQuery. It's much more than saving a couple lines of code or knowing the native way to accomplish the most basic version of a task. jQuery's real benefit is preserving simplicity as your needs grow more complex.
Right off the bat I feel like the getJSON[1] example is a bit simplistic. Almost anyone using ajax needs to serialize data, handle errors, prevent caching, etc. jQuery has thought about all this[2].
Don't get me wrong -- most of my work has been without jQuery, but that means I know exactly how much work it is.
The Good:
The format is a nice way to show people (who really don't know otherwise) the native JS plumbing.
"The number of people who don't know that jQuery != Javascript is too damn high". So to help combat that, I really appreciate the idea behind this site.
It's great to show side-by-side how jQuery isn't "magic", since many people seem to learn jQuery these days without even knowing the first thing about Javascript, but I just think it should be presented with a slightly different premise.
[1]: http://youmightnotneedjquery.com/#json -- side note, why did they set the handler after the `send`? It seems like that could cause problems if the result was returnable quickly, such as from cache, though I haven't tested it.
[2]: http://api.jquery.com/jQuery.ajax/#jQuery-ajax-settings