e.g. ad-driven vs freemium vs subscription, quantity and types of advertising, etc.
Focusing on making the best product/"features and experience" without paying (enough) attention to how it's supposed to make money to sustain itself and fit into the world at large, is exactly how NeXT wound up with fantastic computers and software that no-one bought.
e.g. if they say "tumblr's going freemium" the follow-on questions of "how do we differentiate the experience of free vs paid and how do we communicate the value of the upgrade?" are experience questions that need to be answered and designed in a holistic and considered manner. [1]
[1] And that's why I say those modes are absolutely part of 'features and experience'. Flickr just switched between two fairly-similar freemium models and we power-geeks had a hundreds of comments debate over whether the experience/value jived with the offering and/or was communicated cleanly.