AirPlay is meant to stream the A/V output of a device to another device, e.g. tv or stereo. While DLNA could do the same, DLNA is more meant as media server and player. The N9 does it remarkably well, thanks in great part to the built-in Rygel server. TweakUp and PushUp enhance its functionality even further.

DLNA is the commercial variant of UPnP. DLNA is more strict and has certification. But it's an open protocol and I use it several times a week to watch media stored in my linux nettop on my Samsung-tv, which has remarkable support for DLNA.

Weird thing is that Android doesn't seem to have DLNA/UPnP support out-of-the-box. It's up to the manufactures as HTC, Asus and Samsung to add this. From what I've seen that's not always as seamless as on the N9 and N95(!)

Also, Samsung is now promoting their own protocol for media sharing between their Android devices and tv's. I don't know whether this is an extension on DLNA, more like AirPlay, or something different altogether. It does however seem to be yet again another proprietary protocol adding to the vendor lock-in problem. Given their huge success with their mobiles it might seem like a good business strategy (like Apple, Microsoft, Google), but again bad for consumers.

They won't drop XMPP (yet!), but they will drop XMPP-federation, according to Ars Technica.