How about the google apps route as an alternative to freemium? 1. Give it away for free for a long period to build a user base, get feedback and iterate. 2. A

How about the google apps route as an alternative to freemium? 1. Give it away for free for a long period to build a user base, get feedback and iterate. 2. After a while, switch to paid only for all new users. The old users continue for free so no-one has a right to get annoyed. Seems a pretty good option to me.