the story is breaking (and I'm not going to track it tonight) so what follows is mostly speculation as to what happens when two players (Amazon and Google) compete for different halves of the electronic book in your hand world.
First, expect these decisions to be fought by Microsoft at every step of the way; Microsoft has been being squished out of this market over and over again (with the Zune, with MSN Search, and with MSN Books all meeting a mediocre fate).
Second, expect further restrictions on text to speech based on the Kindle decisions to restrict that function; not good for the visually impaired.
Third, expect a bunch of people to try to liberate their content from Stanza and redo it on some new version that looks about the same, either as a brand new project or something that gets done over and over again starting with Alice in Wonderland and not getting too much further.
My iconic application for mobile phone based readers is reading (or listening to) Kafka's The Trial while waiting for jury duty; let's see in a year how this acquisition changes that experience.