Sweet. My very first LifeHacker "entire site replaced by the homepage" sighting.
As a result of their genius idea to use hashbangs instead of proper URLs, in conjunction with their use of 3rd party (and therefore guaranteed thoroughly debugged and awesome) ad-serving javascript, that link takes me to the LifeHacker homepage with no Seinfeld article in sight.
Opening Chrome's inspector, I see this:
Unsafe JavaScript attempt to access frame with URL
http://uk.lifehacker.com/#!281626/jerry-seinfelds-productivity-secret from frame with URL
http://www.facebook.com/extern/login_status.php?api_key=82da475aae3dff17ef28332d6a2f9501&extern=2&channel=http%3A%2F%2Fuk.lifehacker.com%2Fmodules%2Fblog%2Fxd_receiver.html&locale=en_US.
Domains, protocols and ports must match.