HN user
I think the problem is people are expecting all the functionality of the iPad, this is simply a e-reader on a little bit of steroids. For me the device has been good, the issue with the .mobi files confused me also but really they just appear in the Doc section. If you go to this expecting for an iPad, you will hate it. If you want a simple e reader that lets you browse the web and download some apps, then its great.
When I first started coding I had a huge fear of breaking something as I got more experience and got more comfortable that fear went away, its always a little there but nothing to stop me. Now I struggle with the "beauty" of my code. Will people think that my code is ugly. I will add "Code Fearlessly" to my arsenal of things to repeat when I am scared...the other one I like is "there’s almost no code worse than no code." by Nathaniel Talbott.
I am confused with your fear. Google is just utilizing XMPP, they are not creating anything new, its open sourced. Plus the group that developed XMPP were formalized by the IETF.