But I suppose this removes any doubt we might've had about whether she was keen on continuing Mitchell Baker's bright idea of turning Firefox into an ad platform.
Unless you insist that Mozilla shouldn't get funded (or mistakenly think it would not do severely worse if it had a lot less money), then you'd be proposing a pretty big bet to find a different funding source. Essentially, Mozilla is already funded by advertising - on Google, when you use it via Firefox's default search engine settings.
As for potential alternative sources, donations wouldn't bring in near the same amount of money, and the subscription business is still nascent (but still proof that advertising isn't the only thing Mozilla is looking at), and not a guarantee that it would bring in sufficient revenue.
And of course, there's the question of how to fund the rest of the web. That's currently advertising, and if that remains the primary funding source, it'd at least be nice if it could be done without extensive surveillance.