  We analyse the OPE of any two 1/2 BPS operators of (2,0) SCFT$_6$ by
constructing all possible three-point functions that they can form with
another, in general long operator. Such three-point functions are uniquely
determined by superconformal symmetry. Selection rules are derived, which allow
us to infer ``non-renormalization theorems'' for an abstract superconformal
field theory. The latter is supposedly related to the strong-coupling dynamics
of $N_c$ coincident M5 branes, dual, in the large-$N_c$ limit, to the bulk
M-theory compactified on AdS$_7 \times$S$_4$. An interpretation of extremal and
next-to-extremal correlators in terms of exchange of operators with protected
conformal dimension is given.
