One of the useful things about blockquotes is that you can specify where you’re quoting by adding a cite attribute. But current browsers don’t offer you an interface to use this information. Sounds like a job for greasemonkey! So I wrote cite.user.js to get around it.
Unfortunately, I should have looked around first—I might have seen Citeable Blockquotes, which does what my script does, but more and better. Ah well. It was an interesting learning experience; it took only minutes to put together.