After a while of scratching my head i think i have found the answer why my traffic has dropped off and im putting down to dup pages. On my busy site i have a search page of products and google started to crawl these and initially gave me 3 times the original traffic. Since mid-may this has dropped off and im noticing that google has turned its back on these pages i feel this maybe dup pages. Google is still happily crawling all pages, yet when i do a site:domain search though these appear in the index there is no cache. so how should i approach this? Can i canconical the query string from product=widget&productmodel=amkewidget&min=0&max=5000 to upper limit product=widget&productmodel=amkewidget&min=0&max=10000 ?
or should i write a script to noindex,follow anything that doesnt = product=widget&productmodel=amkewidget&min=0&max=10000