We've started charging new users and the conversion rate has been good. Now the question is, how do we transition our existing free users? There is a chance some people are gonna get pissed (even though they've been using our service for free).
Are there any best practices on what to do in such a situation? The first thing that comes to mind is to offer a discount on the yearly plan. Anything else?
[0] - https://lookastic.com
I don't think it's such a big deal anymore: users are already conditioned to expect entire free services to be gone tomorrow (somehow Google with Plus, Reader... comes to mind ;), so moving to being there but paid is not such a big deal.
Unless you promised it will be free forever (eg for beta testers etc).