icebraining writes with a link to Ars Technica's look at the recent rejection of WebP by Mozilla Developer Joe Drew.
"Building mainstream support for a new media format is challenging, especially when the advantages are ambiguous. WebM was attractive to some browser vendors because its royalty-free license arguably solved a real-world problem. According to critics, the advantages of WebP are illusory and don't offer sufficient advantages over JPEG to justify adoption of the new format. (...) 'As the WebP image format exists currently, I won't accept a patch for it. If and when that changes, I'll happily re-evaluate my decision!' wrote Mozilla developer Joe Drew in a Bugzilla comment.'" However, as the article explains, Google sees enough value in WebP to add it as a supported image format for Picasa.