Block quotes citation idea

[Aaron Swartz]

>     > Now is the time for all good men to come
>     > to the aid of their country.[1]
> 
>     [1]:http://example.com/ "Possible Title"

Something like this might be nice, but I think it should render in the
HTML, since, to my knowledge, there's very little support for
blockquote cite attributes in browsers. What I do is:

> MonkeyFest '98 was an absolute blast. ([cite](http://john.rollins.org/blog/003932))

or when the author isn't clear: MonkeyFest '98 was hailed as "an
absolute blast" ([John Rollins](http://john.rollins.org/blog/03932))
that overwhelmed crowd.

Wikipedia has a thing where [http://somelink.org/foo] gets turned into
<a href="http://somelink.org/foo">[1]</a> (with the number increasing
each time it's used). I've found I sort of miss this technique when
I'm using Markdown, even though it's not the prettiest thing.