So I just discovered that a web site I read from time to time, which has never had an RSS feed available (and believe me, that always pissed me off), actually has an Atom feed.
This is the first time that something I want to keep track of is accessable via Atom but not RSS. I hope it won't be the last.
Of course, this would be considerably cooler if NetNewsWire, my aggregator of choice, had Atom support, but I'm told it's on it's way, so I'll just have to wait patiently for the time being.