Last FM is down due to the leap second apparently:

"Some of our systems were adversely affected by the leap second last night, and as such some users may encounter difficulties accessing their libraries or starting personal stations. Our engineers are aware of the issue and expect to have everything up and running shortly. We apologise for any inconvenience caused by this in the meantime. "

Posted about 6 days ago by jon

Could some one more knowledgeable in IT explain how this could have happened?