The WHATWG now has a patent policy, the WHATCG. We will keep using the same mailing list, the same IRC channel, the same web sites, but now sometimes we will publish through the WHATCG as well for patent policy purposes per the W3C Community Final Specification Agreement.
If you could previously not join the WHATWG because no patent policy was in place, now is the time to reconsider. If you are unsure how this applies to you, then it most likely does not.
Ian Hickson made a proposal to unify Web Intents with registerProtocolHandler() and registerContentHandler(). The Encoding Standard now has all its decoders defined. This is the WHATWG Weekly.
The big news this week is the new dialog element. Introduced in revision 7050, along with a new global attribute called inert, a new form element method attribute value "dialog", and a new CSS property anchor-point.
Yours truly updated the Fullscreen Standard just in time for the dialog element. It defines a new CSS ::backdrop pseudo-element as well as a new rendering layer to address the combined use cases of Fullscreen and the dialog element.