According to a blog post by Simon Phipps each user who is looking to make use of the cross-license has to enter into a contract with Google and as most of the open source projects either don’t have the required in-house legal expertise or lack funds to hire a legal personnel there might be no one who will sign such a contract with Google. Further the license is not sub-licensable which means that downstream users will not have the license automatically transferred to them.
Phipps points out that the cross-license is restricted to encoding, decoding, transcoding and playing of VP8 video – this means that if an application developer adds functionality into this code that goes beyond the above four things, the cross-license doesn’t apply. The open source advocate notes that there would be uncertainty as to whether a specific program is covered by the license or not. He goes on to say that the draft cross-license is in conflict with the Open Source Definition (OSD).
Raising the point of sub-licensing, according to clause 3 of the OSD, any derived work has to be available under the same license as the original software and as the cross-license doesn’t fulfill this criteria, Phipps notes, “Once again we’re left with our fingers crossed.”
Phipps goes on to add, “Google’s making the right noises, but this draft agreement seems like a particularly unworkable approach for free and open source software.”