The problem with Buy.com is that "buy" is a word (or call to action), not a brand. I've probably seen the buy.com URL around here or there, but the word is so pedestrian, it doesn't ring any bells.
Calling out Rakuten for "meaning nothing to most people" is kind of silly. What about Pepsi then?
Maybe this was due to poor marketing on Buy.com's part?
This finally explains to me why I've been seeing all the graphics for the Buy.com campaigns change to 'Rakuten Buy.com'. I didn't know that Buy.com is a Rakuten brand. Honestly, I didn't know it was a company outside of Rakuten LinkShare. TIL.