According to a forum, Tony Stark’s site went into first place in Yahoo UK & Ireland (worldwide search) within few days for his main search term. A month later, it gradually dropped to 8th place. l2edlvova says that the drop can be numerous problems, it could indicate two things – Tony Stark’s site are not doing good enough or his competitiors are doing better than him.
http://forums.seochat.com/yahoo-search-optimization-60/big-drop-off-in-yahoo-259525.html