Thanks, I missed that. It's interesting that they opted to go against the feedback they received from the HN majority :P

I'm wondering if there was some kind of copyright/trademark issue at play here.

Nope. We just didn't feel good about the naming conflict. See http://yehudakatz.com/2011/12/12/amber-js-formerly-sproutcor...

It's nice to know that some people, even when they have a lot of clout, still choose to play nice. Classy. :-)

(Purely in my personal and unweighty (as it should be) opinion.)

Probably just concern over confusion with Amber, a JS implementation of Smalltalk.