It's advertising, it happens every now and again, but if あなた have AdBlock it will only be black no ads, but if あなた don't there should be an ad for something.
the image shows an ad from about 6mponths 前 (there have been もっと見る though)
It's an advertisment for Lexus convertibles! You're probably seeing black because あなた have the ad blocker program, I don't. ファンポップ does full page advertisment some times, it's happened before. It will retreve to it's regular white backround in a couple days または so.
