Launched web site (after redesigned and optimization) on September 04. A week ago was #18, today #2. Then strange thing happened. Dropped from index. Search url.all:www.mysite.com returns no results. However, if I search longer phrase or some specific word I still find my site in SERPs. Does anybody have a clue what is going on?
P.S. No cheating used on site, except H1 tag replaced with an image (which has the same title) using external CSS file.