That's the great thing about Two by Two - it can sit just as comfortably in the Strategy / Euro section as it can in the Mass Market aisle.
For the record, River City Games caters to a pretty wide range of markets. There's plenty of Rio Grande and Zman and Fantasy Flight stuff deeper down the aisles, Spiel des Jahres winners and other family games down the middle, jigsaw puzzles along the back wall, a couple of towers of card games, etc. This particular end-cap display is right by the cash register where it opens up into the billiards and poker table display area. They put a lot of chess, backgammon, and abstract strategy titles down that aisle to ensure the billiards and poker people see something familiar and decor-worthy that might lure them back into the boxed games area.
Their selection doesn't run very deep but it's generally pretty well chosen.
Dragon's Den in Saskatoon also reported selling out of Two by Two when I talked to them over the New Year. After playing the game, they placed it next to other family-oriented games such as Dixit (which also saw a lot of play in my family this Christmas - what a delightful game!).