FamilyLink pulled a fast one on the 19 million users of its We’re Related Facebook application today.

We’re Related users received notifications that Barack Obama had confirmed them as a fourth cousin once removed. Genea-Musings' Randy Seaver posted his notification and the linked pages explaining the “relationship.”

A Learn More link at the bottom of the explanatory page fessed up about the April Fool's Day prank.

Some think the joke is funny, some don’t (and some who didn't click through probably believe it). Either way, FamilyLink is getting a lot of buzz. According to the AllFacebook blog, We’re Related is experiencing five times its usual traffic today.

FamilyLink CEO Paul Allen linked to We’re Related users’ Tweets on Twitter.