[embolalia]

The way to remember it is just that you're parenthesizing the URL. Naturally, you might write it "look at this thing (http://example.com)" - in Markdown, you do the same, but with brackets to indicate where you want the link to show up. "look at [this thing](http://example.com)"

I don't buy for a second that <a href="http://example.com">this thing</a> is more intuitive than that, even if you disagree about the specific brackets used.

[pessimizer]

"a href" isn't intuitive, but it's memorable.

[smackfu]

Yeah, honestly, I think more verbose formatting is much easier to remember than a bunch of punctuation.