Shane Law of Sydney sent me a link to a post he did recently on the difference between real estate photography and Interior Photography. Shane shoots both real estate photography and interior photography so he probably thinks about this more than most of us.
This distinction between real estate photography and interior photography may seem obvious to more experienced shooters but to for beginners it's important to think about what the purpose of each photo. That is, what are you trying to communicate and illustrate with each shot? The two different goals are:
Shane gives several good examples of photos of the same room that illustrate these difference in photographic goals.
The thing I always point out to people that's different between real estate photography and Interior/Architectural photography is the training of the client you are working for. Interior designers and architects have extensive training in the visual arts so they will have much higher expectations than real estate agents who typically don't have any training in the visual arts.