What, exactly, makes the toric code a quantum error-correcting code as opposed to any other string-net model? What makes it special? The way I understand it, it's a normal string-net model on a torus, where the stabilizer space for such a model is 4D and thus it can support two qubits. Is this space 4D because of the periodic boundary conditions on the torus?
Also, I am a little confused what the toric code tells us. Is it a static theory of anyons, or can we simulate braiding statistics?