From 2007:
I have a sneaking suspicion that my main contribution to the sum total of human happiness is the fact that I go well out of my way to provide a traceable source for this blog’s daily almanac entry. Cyberspace is cluttered with millions of pithy quotations, most of which are unsourced and thus unreliable. Not infrequently a bit of sophisticated surfing will allow you to pin down their sources, but too often they remain firmly rooted in the realm of conjecture.
Off the top of my head I can think of only two favorite quotations that I’ve never been able to trace to their original sources…
Read the whole thing here.