This question could be much wider in scope than AWS, so I'm surprised we don't have a wider variety of responses that touch upon everyday B2C ... bookstores (vs the original Amazon), shoe stores (vs zappos), home services (vs Amazon's task rabbit like service) etc. (Yes, I know this is hackernews!)
For my contribution, we're working on something where we expect AMZN to go far deeper into in the not so distant future: furniture. We're "safe" now because AMZN doesn't let you touch, feel and smell their offerings. That clearly could change if they continue to expand their physical retail footprint.
AMZN's impact on us: TBD. We think they may disappoint a lot of consumers. We focus on vintage and artisan furniture to cater to those that will want more variety and character.