The holiday season is the best possible time for a boycott of any retailer. Last-minute shopping hasn't happened yet, and for most people, there are good alternatives for most of what Amazon carries.
But I'm saying that the vast majority of Amazon's customers are not software developers. They're soccer moms, busy middle class honest workers who don't know a damn thing about AWS or even that Amazon had anything to do with wikileaks.
They don't care. They'll buy from wherever is cheapest/most convenient.
Well, it's not just software developers who are fired up about free speech but putting that aside more a moment...
The soccer moms, teachers, honest workers, etc. in my and my SO's family would almost certainly honor our requests to "please don't get us anything via Amazon" -- especially if we give them alternative sources. Some of them would be interested enough in it that we'd discuss it and probably convince at least a few that this is a serious problem and they want to get involved. Most people have at least a few friends who are sympathetic; as people start posting about it on Facebook, others will see and at least a few will decide to get involved. Plus there are some family mailing lists (mostly used to exchange bad jokes) and people there tend to defer to my expertise on computer stuff. So we'll probably pick up a few more there ...
And internationally, my guess is that feelings are a lot stronger. It's fascinating watching the discussion on Twitter -- there's so much in other languages. Initial momentum for a boycott seem strongest in Spain right now ... and no surprise, given the revelations in the cables. From abroad, it looks like an American company trying to censor the world's access to information, so I could imagine a boycott having a bit impact there.
The average consumer has no clue that amazon has anything to do with the tech industry. To most people it's just an online store.