This is good, because it will help promote better standards across mobile application development. Until now, developers have been all over the map in terms of how such apps or mobile-enabled sites are created.
So, the big question in my mind — what sort of domain name do they recommend for mobile apps?!? Do they recommend using the .mobi top level domain (“TLD”)?
The answer to this is, they’re suitably neutral about what the TLD should be. They recommend short, short, short — so, they recommend  using domains without subdomains such as leaving off the “www”. This is good, because as I’ve pointed out, .Mobi TLD isn’t good  since it was launched with heavy rules and I think consumers should only be expected to remember one, central domain name for a site. Even better, the W3C recommendation falls in line with the No-WWW Initiative  which recommends setting a site’s primary domain to be the non-WWW version.
So, just based on the W3C recommendation, one might want to avoid using .Mobi extensions because it adds yet another letter to the domain name that cell phone users would have to type in.
Interestingly, one of the W3C editors working on the mobile document is Jo Rabin who is the Director of Industry Initiatives at dotMobi (mTLD Top Level Domain Limited).