Hi there rdwarn. Corner placement is used to help use room acoustics to boost the bass signal. So not only is your subwoofer working, but the room is also working to your advantage. Having a subwoofer shoot at the wall sounds a little gimicky, like maybe someone is taking this method to the next level by having the LFE bounce off the wall. Simply placing it in the corner will do, I don't believe you need to face it against the wall. Besides, it looks kinda ugly with all those cables and knobs facing you (definitly low on the WAF).
Behind your couch in a corner is probably fine, but make sure that you're not blocking too much of the signal path. Maybe the low low LFE is passing through your couch, but if you have a high enough crossover (80 Hz) you may be missing some of the sound as even at that level the bass is somewhat directional.
Generally the best place to put a subwoofer (if you are using only one) is up with the front sound stage. But it comes down to what sounds best to you, and if you have a SPL meter and an Avia disk you can check where certain subwoofer placements cause spikes (boost in the Hz range's db).
