Tyler Cowen passes this along

Another contrast is between people who type in "is it wrong to" vs. people who type in "is it unethical to."  If you type in "is it wrong to" the first suggestion is "is it wrong to sleep with your cousin."  Number two is (yes, I tested it in Google): "Is it wrong to sleep with your step dad after your mom dies."  If you type in "is it unethical to," the first suggestion is "is it ethical to sell customer information."

Emphasis mine

You might think this says something about what the American people find ethical or unethical. But it says a lot more about what we find funny.

It seems that all of the references to this phrase eventually point back to a single question posed to a “dear Abby” type web personality.

Dear Eve,

Last spring my Mom was killed in a car accident.  I came home from college at the end of the semester to help my Step-Dad pack up her things and we spent a lot of time talking about my Mom. One night we decided to open a bottle of her favorite wine to toast her memory, and before I knew it my Step-Dad and I were making love on the living room floor.  I always had a crush on him and was jealous that he married my Mom. He says he loves me and wants to spend the rest of his life with me. I feel like this is the way things were supposed to be but I’m afraid to tell our friends and family.

Eve, what would you do?
Mistress in Mourning

The original post is lost gone but it seems that it was copied so many times that it now dominates the “is it wrong responses “

This goes to show that while richly diverse subcultures can come to life on the web (fat tails) a single instance can also grow in popularity to such an extent that it dominates millions of queries (fat spikes).

And yes this is post and to a much larger extent, Tyler’s will generate more queries on “Is it wrong to sleep . . .” By next week, perhaps it will be number one.