What's the worst thing that could happen to Google?
tsally: A scandal related to personal data large enough to spook your average consumer.  We're talking serious stuff, like records being sold to criminals or given to the government without a warrant.  The only thing that could cause a user to get over the large cost of migration is a massive breach of trust.It doesn't even have to be related to search.  A scandal involving Gmail or Google Voice would have a large impact on search.