Here’s a compilation of 7 interesting takeaways. You can click on the takeaway-number to read the original answer on Reddit.
1. Magento 2 still uses Zend 1 because of a negative cost/benefit analysis
In other words: it would take too much effort to replace all the usages of Zend 1 with, for example, Zend 2 when there were so many other changes to be made. Magento 2 does however not completely rely on Zend 1. There are plenty of components of Symfony and Zend 2 being used.
2. Magento 2 will supply database migration tools
Though the migration process is something which is still work in progress, there are already plans to offer migration tools for easily moving over Magento 1.X media and database entries such as product, customer and configuration data. Because the platform has heavily changed, automatically converting themes and modules is not realistic. There will be improved documentation to make that process as easy as possible.
3. The magento2-community-edition repository is for specific Composer builds
4. More Magento 2 code examples can be expected around the end of March 2015
In the works is a set of examples demonstrating Magento 2 technologies. One of those examples will demonstrate how to add a custom payment provider to the Magento 2 platform.
5. Magento 2 will not ship with NoSQL integration
But, due to the Service Contracts it will be drastically easier to implement NoSQL database layers in the future in very specific places. Implementations will be considered after the General Availability release.
6. Extension developers should get to work when the Developer Beta Release Candidate lands
Recommended is to start working on extension ports when the developer beta release candidate is released. According to the schedule this will be in the first quarter of 2015. Which is anywhere between now and a few months from here.
7. Magento Live will not expand to new countries this year
Just because we picked 7 interesting takeaways, doesn’t mean the rest of the AUA isn’t interesting. Be sure to read through all the questions and the answers if you have some time on your hands. The AUA has been terminated but if you still have questions, the opening post has some tips on getting in touch with the Magento 2 team.