> That's the font you are reading this comment in, in fact.
Wrong. One of my favorite features of Firefox is that I get to choose whether websites can override my fonts. And they can't. Serifed Georgia is default, Ariel if they request sans-serif, and Consolas for monospace.
Yes. I just reloaded the Dev Fonts page with and without locked fonts and it only downloads them when the fonts are unlocked.
I forgot to mention that one may also set a minimum font size. That one does occasionally break a layout here or there, but it's worth it for easier reading.
Wrong. One of my favorite features of Firefox is that I get to choose whether websites can override my fonts. And they can't. Serifed Georgia is default, Ariel if they request sans-serif, and Consolas for monospace.