These examples all have simple URLs, but they don't have to. I once built up a complex Google query to find XKCD cartoons by keyword: xkcd %s site:xkcd.com -site:forums.xkcd.com -site:fora.xkcd.com -site:blag.xkcd.com. Of course, I saved it as a bookmarklet. Now any time I want to search for a cartoon, all I have to do is type xkcd keywords.
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