My site dropped from no.1 spot to nowhere. Google tech people replied to my email telling me I must have hidden text or used some kind of ‘illegal technique’! Why don’t they just admit it’s their mistake?
Standard reply
It’s a standard reply, nothing else. I would imagine that 9 times out of ten when Google get an email about a site that has dropped into oblivion it has something to do with using techniques that go against their webmaster guidelines. It may not be the case with you but from their perspective I should think it a reasonable reply in the circumstances.
There seems to be some confusion about ‘penalty’
A ‘penalty’ is applied to sites using tricks and sneaky stuff to boost their rankings in Google. A good recent example would be BMW who were using one page for the search engines and another for the web visitor. Since this was contrary to Google’s guidelines, BMW were removed from the index entirely — they were penalised (http://www.mattcutts.com/blog/ramping-up-on-international-webspam/).
Filtered
Another type of ‘penalty’ although it really is a...