The character of Apostrophe Man was created by George Richards, editor of The Sydney Morning Herald's popular Column 8. Richards was the column's longest serving editor, holding the post for almost 16 years until his retirement on January 30, 2004.
Often misunderstood as a nitpicker, or as someone who Richards was consulting to correct the mistakes of the many (or as Richards himself), Apostrophe Man was actually rather more like Voltaire's idea that if God did not exist, it would be necessary to invent him. The reasoning goes like this: ask your friends if they know how to use an apostrophe and they will all say yes; every day, one comes across examples of the misuse of apostrophes, some of them atrocious; therefore it cannot be anyone's actual mistakes. Rather, there is an Apostrophe Man, akin to one of Neil Gaiman's American Gods who runs about mucking up everyone's otherwise perfect usage.
Richards would typically start (yet another) apostrophe subsection of Column 8 with a sentence like: "Julie Bennet writes that Apostrophe Man has struck again, causing a sign in Chatswood to read "Men's, Ladies's Haircut's". It was a measure of the popularity of the old front-page Column 8, that once cited in this fashion, signs and billboards in the Sydney area were often quietly and quickly "repaired". It's also an indication of Richards' influence at the paper that he was allowed to actually print errors on the paper's front page, rather than simply allude to them.
Leading the fight against the ravages of Apostrophe Man (apart from Richards in Column 8) are bodies like the august Apostrophe Protection Society of Boston, England, started by one John Richards (no relation), and several users on this very site.