Rajesh Pandey, writing for iPhoneHacks:

Interestingly, Apple also seems to be adding support for multiple voice recognition in HomePod. The icons discovered in the Home app suggest that Siri would be able to recognize an individual’s voice and offer them personalized results.

Although the Echo offers multiple user support, you have to tell it to switch users. I’m not aware that it supports voice recognition, so this would be a big differentiator for the HomePod. And of course leave it to Apple to allow for easy muting of the Siri, for privacy-minded users. That’s the benefit of Apple’s business model not being tied to advertising.