Matt Cutts gave us another weather warning or should we say a warning about another update. This time it is the EMD update which is designed to remove low-quality and exact match domains from the Google search results.
The idea is to prevent people coming up with perfect domain names that match the keywords that they are going to be buying. Matt Cutts wants people to be a domain name that works for people.
If your website has suddenly disappeared from Google in October and the domain name is an exact match of keywords then you are likely to have been hit with the EMD update.