No special development toolset required, just publish a text file with the proper metadata and you're good to go. They're even planning an integrated payment system.
This could be huge.
Hello back, proprietary software. I still don't like you, even with new clothes.
I cannot see how the apps are meant to be "installable". Will Google run them on the AppEngine (or similar)? What if my app requires a set of services running on another machine?
I think at the most basic level the "installation" process simply sets up shortcuts to existing web apps in Google Chrome.
There's the ability to install serverless (static file based) things too; the example given is browser-based games.
My knee jerk reaction is this is a giant step towards the web as we know it becoming "GoogleNet". I hope they get some sizable competition in this space.
No, I don't think so. Until the URL concept is dead, it will always be easier to promote your web site directly, via multiple reviews, affiliates, other software, etc etc. Google app store will be just one of these.
It's HTML and javascript ffs, there is no lock-in.