  We analyze the possibility of extracting S matrices on pp waves and flat
space from SYM correlators. For pp waves, there is a subtlety in defining S
matrices, but we can certainly obtain observables. Only extremal correlators
survive the pp wave limit. A first quantized string approach is inconclusive,
producing in the simplest form results that vanish in the pp wave limit. We
define a procedure to get S matrices from SYM correlators, both for flat space
and for pp waves, generalizing a procedure due to Giddings. We analyze
nonrenormalized correlators: 2 and 3 -point functions and extremal correlators.
For the extremal 3-point function, the SYM and AdS results for the S matrix
match for the angular dependence, but the energy dependence doesn't.
