I had a site on the front page for the past two months for 4 keywords and they were #1 for about the past month. Two days ago they dropped in yahoo rankings from #1 to #3 and today in Google they dropped from #1 to #20-#30. I haven't done any recent backlinking and even when I first started the site I was higher than rank 30. I was immediately put at #15. I'm hoping this is most likely temporary. Anybody have any idea what could cause this?