Steam doesn't release sales numbers like console retailers.
http://www.vg247.com/2011/12/16/skyrim-ships-10-million-units-worldwide-sets-steam-record/
With 280,000 concurrent users on launch day, Skyrim http://www.vg247.com/2011/11/11/over-200000-people-playing-skyrim-on-steam/. Sales-wise, http://www.vg247.com/2011/11/16/skyrim-sells-3-5-million-units-in-first-48-hours/, 3.5 million copies of Skyrim had been snapped up, eating up half of the publisher’s initial shipment of 7 million.
280,000 versus 3.5 million (a majority of which are 360 and PS3 sales, which you'd know by looking at http://www.gamesas.com/topic/1317287-skyrim-sales-discussion-10-million-retail-copies-shipped-as-of-dec-15-thread-2/page__fromsearch__1 thread. Then again, the 280,000 is from launch day for Steam, not the first 48 hours, but it's nowhere close to 3.5 million.
Motion controls is a gimmick that will die soon enough.
http://en.wikipedia.org/wiki/Kinect
10 million units of the Kinect sensor had been shipped by March 9, 2011.http://en.wikipedia.org/wiki/Kinect#cite_note-10-million-1 Having sold 8 million units in its first 60 days on the market, Kinect has claimed the http://en.wikipedia.org/wiki/Guinness_World_Record of being the "fastest selling consumer electronics device".http://en.wikipedia.org/wiki/Kinect#cite_note-10-million-1http://en.wikipedia.org/wiki/Kinect#cite_note-Gamasutra-record-19http://en.wikipedia.org/wiki/Kinect#cite_note-CVG-record-20http://en.wikipedia.org/wiki/Kinect#cite_note-Guinness-record-21 According to Wedbush anolyst Michael Pachter, Kinect bundles accounted for about half of all Xbox 360 console sales in December 2010 and for more than two-thirds in February 2011.http://en.wikipedia.org/wiki/Kinect#cite_note-132http://en.wikipedia.org/wiki/Kinect#cite_note-133 More than 750,000 Kinect units were sold during the week of Black Friday 2011.http://en.wikipedia.org/wiki/Kinect#cite_note-134http://en.wikipedia.org/wiki/Kinect#cite_note-135
Sure, keep thinking that.
Just look at how it was implemented for Mass Effect 3. That could easily have been done with Skyrim, especially when you consider the use of Thu'um in-game.