I have just received a malware notification from Google today, claiming that my site has suspicious content and they will put a warning in their search result. I checked the Stopbadware guidelines but could not find any problem with my site. A Google diagnosis also confirmed that there was no suspicious content or malicious software hosted in my site over the past 90 days. The only problem is my site is hosted in a network of >40000 sites and some of them have suspicious content that can download malware to the visitors' computers. My site is hosted in a shared server so I can't control the content of the other sites (and these sites may or may not know they serve suspicious content themselves). I wonder if the more experienced webmasters can suggest ways to tackle this problem. I have already contacted my hosting company and asked Google for a site review and explained the situation.
Thanks in advance for your help.