But the next stage in the evolution of e-mail messaging -- mail reputation and accreditation -- is even more complicated, with vendor-backed services such as Bonded Sender, Habeas, Goodmail , TrustE, SenderBase, Spamhaus, Spamcop, SenderIndex and SenderScore providing overlapping services and, in some cases, competing with one another.

The result is that enterprise IT staff are overwhelmed with options, but have little guidance about how to assemble a working solution that will spot and block fraudulent spam messages, Wong said.

"We need to build The Reputation Store where folks can just go in and buy what they want," Wong said.

At Principal Financial Services in Des Moines, Iowa, Corey Null said he passed on the Summit this year, after attending the inaugural show in New York City last April.

"The issue kind of dropped off for us," Null said.