The Prototype period will last several months, as we have planned patches and content to roll out gradually. Our goal is to work through each two week period to deal with various bugs that might come up and help players have fun in our world! We have a release schedule for major features and we want to make sure that everything is functioning properly before full release.
It is our goal to support Prototype 2 for as long as possible. As those before me said, unlike Prototype 1, we can update the server with regular content updates now. This means you will see a new feature added every 2 weeks, with smaller content updates in between. Once there is enough content to justify a full release, we will think about the "Prototype 3" - full release. At that point, we will reward our current testers and make sure their work has not gone unnoticed.