VP9 is an open and royalty free video compression standard being developed by Google and the successor of VP8. If you're into video, you'll be happy to know that Google Chrome Team is working on it right now.
I don't think Mozilla supports WebP, +Sushubh Mittal. My friend and I were just discussing this last night. He found the Google page where they compared WebP and PNG images and he couldn't see any of the WebP images. Silly personal politics on Mozilla's end it seems from bug reports.
+Christian Gati Righto. Googling tells me that Mozilla indeed rejected WebP image format. :\ I am waiting for Imgur to add support for it as well. Need a image hosting service that support webp files! Yes, I do know that I can upload WebP images on Google Plus. That works great!
+Darren Neimke According to a presentation by Google, VP9 is ~7% behind HEVC/h.265 in terms of quality/bitrate when they tested VP9 in Q4 of 2011 (They started developing VP9 in Q3 2011). Their goal is to become even better than HEVC.