Actually, when I see MeshTags I assume "they're" just trying to sell me an cumbersome url shortening serivce.
By the way, the assumption that people don't/won't use QR codes is wrong. Here's one example: Chinese associate QR codes with product information (ex.: scanning a code on a bottle of soda).
Many people don't use QR codes but I think your assumption (QR codes will evermore be perceived as commercials) is totally off base.
Where Meshtag fits in is that it's aimed at users and not companies. I think a large reason most people don't scan QR codes is because they assume they're just trying to sell you something. But if you saw a meshtag that somebody drew on a wall somewhere, wouldn't you be curious?
Also, thanks for all the feedback! I have dreamed of being on hacker news since I started coming here. Any UI/UX designers in the Boston area, hit me up if you want to get involved!