Dr. Weevil is running daily entries from Ambrose Bierce' Write It Right. For example, today's entry is:
As—as for So—as. “He is not as good as she.” Say, not so good. In affirmative sentences the rule is different: He is as good as she.
Or to put it another way, this a catalogue of losing and lost battles against "meaning slippage" in the English language. Still, fun daily reading.