Slashdot/Reddit/Facebook etc all build communities, when they get too large they splinter until they become increasingly specific. You've done the opposite. I think you are going to need to group common products, then gradually break it out. ie, food -> deserts -> cakes -> chocolate cake -> chocolate cake from <shop> etc
That's how I pictured it, users scan all the bar codes they have access to and it builds similarity profiles.
I pictured scanning all my CS books for example, and I'd probably end up in a group with everyone from my class at school who did the same, for example.
As you said, I tried to keep the room name general so it wouldn't be too scattered when the barcode is scanned. So, if someone scanned for a cake, it currently deletes the chocolate cake and brings up that cake brand, but later, users will be able to create a room for chocolate cake with the same barcode if they wish.
