Firefox. In the web generation before Firefox, there was Apache. Before Apache, HTML + HTTP. They're all everywhere because they're free to be so.

Only what's free* can be trusted as the web!

* free = as in, free speech

Only new things which add big, public, freedoms to the web deserve a note for helping evolve "the web". Firefox is there now.

Firefox is notable because the web browser is an essential part of the web, and Firefox freed it and made the browser an asset of the worldwide public.

And, this has changed the web—public interest is more and more affecting how all web browsers work and what one can do on websites (e.g., Microsoft created the original A technology behind AJAX, but AJAX became important because Firefox set it free).

What other developments hold a candle up to Firefox, right now? (btw, Happy Birthday Firefox!)

Of course, being free software or patent-free isn't enough. We need these developments to be widely embraced—i.e., we, the worldwide public, need to take an active interest in their success.

For example, VLC could someday be the Firefox of audio and video on the web. Part of what will be notable is when/if a lot of people embrace VLC and switch away from big-name media players.

What other essential features of the web are not free, yet?