I own Alico Emporium, across the street from Sebass1227's shop. For months I have seen nothing but an unused farm and storage space where they have bought a shop. They aren't selling anything and honestly it's just ugly. I'd personally like to see nice use of shops and actual care for them.
Examples:
http://i.imgur.com/tJ8j1MB.jpg
http://i.imgur.com/G68gYoB.jpg
I think this shop breaks the following two rules for shops:
Ugly Buildings
Don't ruin the inside of your building. Things that count as violating this rule are: just placing random blocks everywhere, using blocks that aren't used anywhere else in the area you bought your shop in, making your building one giant swimming pool, etc. If you do this, all of the offending blocks will be removed and you will get a warning.
Building Usage
You have to use your building. If we sell you a building and you just let it sit there and rot, why do you have it in the first place? After you buy a property, you must build in it within 2 months (Exceptions would be that you're MIA, and have told us that on the forums). If you do not, the building will be taken and put up for sale once more.