This comes from a report from The Information (via Android Police) in which apparently Sony approached Amazon several times about ad placement. Sony had apparently wanted to run ads on its Jeopardy Alexa game, which Amazon reportedly refused to allow them to do. The company claims that putting ads will alienate users (we agree), which ultimately frustrated Sony who felt like they weren’t able to profit from the Alexa skill that they created.
However that isn’t entirely true because one of the ways Amazon is allowing developers to make money through Alexa is through “premium skills”, which are subscription-based skills that users can opt-in on. In fact Sony’s Jeopardy game is one of the skills that is taking advantage of this subscription model, although exactly how many users are taking advantage of it remains to be seen.
We suppose eventually there will come a time where companies will start figuring out a way to monetize its services, but for now Amazon Echo/Alexa users can rest easy about ads not invading their speakers and devices.