  As a consequence of the AdS/CFT correspondence, planar ${\cal N} =4$ super
Yang-Mills SU(N) theory is expected to exhibit stringy behavior and multi-Regge
asymptotic. In this paper we extend our recent investigation to consider issues
of analyticity, a central feature of Regge asymptotics. We contrast flat-space
open string theory in the planar limit with the ${\cal N}=4$ super Yang-Mills
theory, as represented by the Bern, Dixon and Smirnov \cite{Bern:2005iz} (BDS)
conjecture for n-gluon scattering, believed to be exact for $n=4,5$ and
modified only by a function of cross-ratios for $n\geq 6$. It is emphasized
that multi-Regge factorization should be applied to trajectories with definite
signature. A variety of analyticity and factorization constraints realized in
flat space string theory are not satisfied by the BDS conjecture, at least when
the exponential factors are truncate in the infra-red regulator below
$O(\epsilon)$.
