This issue was the main reason that we decided against Google Apps for our email system. If we're running an Exchange or Domino server then even if MS/IBM stop

This issue was the main reason that we decided against Google Apps for our email system. If we're running an Exchange or Domino server then even if MS/IBM stop supporting it we can continue to use everything and plan a migration. Google could turn off decide GMail was unprofitable and turn it off tomorrow, and everyone would be screwed. I went to a Google Enterprise sales event and asked them about an internally-hosted version, but they were very clear that this wasn't something they were considering. You could protect yourself against this by building an internal IMAP server and syncronising it with Google regularly. But that's a lot of work, and maintaining your own email server negates many of the benefits of outsourcing to a cloud service.