Steve Burge recently published a blog post on The Joomla! Community Portal explaining the 3 things that the Joomla community needs to know about the upcoming version of Joomla, due out in September.
Joomla 3 is inherently mobile
"This is the version that will bring Joomla up-to-speed with the mobile revolution that is taking over the web," Burge says. In all of the online research and predictions available now, it's clear that users will be overwhelmingly online with mobile devices, rather than their desktop computers. Joomla 3 will be ready.
Joomla 3 is for "early adopters"
Burge also mentions that, "Initially, Joomla 3 is best used by early adopters, developers and more experienced users." How do you know if you are in one of these groups or not? Well, if you're not sure, you probably aren't. Early adopters are those users that have to have the latest and greatest versions along with all of the newest features possible. They also experience most of the early bugs and issues. If this isn't you, read on.
If you're on Joomla 2.5, stay there
Since Joomla 2.5 is a long term support version, there isn't a rush to move to 3.0 if you don't need to. It is recommended that those users still on 1.0 or 1.5 move up to 2.5 as soon as possible. Version 1.0 has no update support, and support for 1.5 will end later this year.
For more information you can read the full post on The Joomla! Community Portal.