Back in the nineteenth century, when news spread primarily by word of mouth and was often difficult to verify in a timely manner, newspapers used to print gossip and rumors under the heading IMPORTANT IF TRUE — because some of the stories might very well have been true, and if they were true, they were important news.

The same phenomenon now takes place in a slightly different form: Internet users receive all manner of obvious hoaxes and jokes but forward them along as if they were real news, because they might be true, and if they are true, they're important. All of these items have been sent to us — more than once — by readers wanting to know whether they're true.