Maximal estimates for multi-sublinear operators are established
which allow one to apply Nikishin's
factorization theorem to obtain factorizations through weak-Lp spaces. Combining this
with a result of Kalton's,
any bilinear operator from a product of type 2 spaces into the space of measurable
functions factors through a Banach space. Thus, every such operator can be viewed as
a linear operator acting on the projective tensor product. Applications and related
open questions will be discussed.