If you have been missing App Inventor then you will be relieved to learn that it is now available again - albeit still in beta.
When MIT took over App Inventor we users were hopeful, but the first thing that happened was that the public service shut down at the end of December 2011 without any alternative service provided by MIT.
This was not a good start.
Now after two months of testing the closed beta has become an open beta. You can now sign in with, ironically, a Google ID, e.g. a GMail account. So Google gives up App Inventor but still gets to be the gatekeeper! If you have a Google ID then it will simply prompt you for a password. This also raises the issue of what is wrong with OpenID and similar login systems.
But looking on the bright side, now seems like a good time to get involved again, although I think I'd stay away from organizing any educational courses around the facility until it is declared stable:
"Of course, there are glitches and minor errors and lots of room for improvement. We’ll be turning our attention to these improvements, once we have more experience with running the system at scale. We will also be developing more resources and support for using App Inventor as a learning tool. We look forward to working with you over the coming months to build the community of App Inventor educators."
Among the known issues is the problem that MIT App Inventor cannot load projects that are as large as those supported by the Google version. It also reports that some projects have loaded with missing blocks.
What is taking so long to move a stable development environment to an new home is something to wonder about - and MIT is not really explaining the difficulties. We can only hope that things go well and this valuable resource is returned to full working order soon.
One small problem is that App Inventor is not only an excellent educational tool it is also a way to prototype Android apps. How commercial use of the MIT-provided facility will be treated is another interesting question.
One thing that is clear is that while the world seems to be intent on making a fuss about the educational impact of cheap hardware like Raspberry Pi, really valuable tools that could produce a new generation of programmers such as App Inventor don't seem to get the headlines.
Perhaps we should start a campaign with the slogan:
It's the software, stupid!
If you are interested in getting started with the new service keep an eye open for the update on our article: