By way of several support notes, perhaps posted a bit early, we learn that Roku is set to unveil mobile device screen mirroring. It’s not clear if these are the Miracast capabilities originally predicted by GigaOm in 2013 or something entirely different, but we do know the feature is currently limited to Roku 3 and Roku Stick (HDMI) hardware and it’s suggested both the Android or Windows Phone streaming device and Roku reside on the same network for best performance. Beyond straight up screen mirroring, Firefox Video Casting is also revealed and is more Chromecast (DIAL) in presentation. Desktop mirroring is referenced too, but a mechanism to pass the content has yet to be described… also, noticeably absent is iOS. I expect we’ll learn more shortly!
Update: And here’s the Windows 8 screen mirroring support note.