"Instead," De Santis said, "they got a highly trained expert that provided the same service who was merely paid by the hour." Buckle up, bank investors. Just as Citigroup ( C), J.P. Morgan Chase ( JPM), Bank of America ( BAC), Bank of New York Mellon ( BK) and Goldman Sachs ( GS) seek to build on their sterling 2012 performance, investors are facing the next probable victim in the collapsing digital economy: the lucrative merger-and-acquisitions business most big banks rely on for profitability. "It's what you talk about all the time. The Web comes in and forces efficiencies into a market, which collapses that market," he said. "And now it's coming to mergers and acquisitions." Expert Network as iBank Let's be clear: Nobody anywhere near this debate -- that means me, De Santis or anybody I interviewed -- is minimizing the risk folks such as Gilman and Martoma may or may not try to cheat using expert networks. But the sheer scale of these systems makes Wall Street look itty bitty by comparison. Gerson Lehrman, who confirmed that De Santis had used its networks, confirmed it had more than 350,000 registered individuals on its micro-consulting platform, which is used by more than 1,000 institutional clients and growing. "We've heard people say we can be disruptive to traditional industries," Alexander Saint-Amand, president and CEO of the Gerson Lehrman Group, wrote me in an email. "But we've seen we can not only be an asset to private equity firms and corporations who are engaged in M&A activity as well as to the research and advisory firms working on these deals." Considering that the company has arranged more than 1 million such engagements over 10 years, Gerson has clearly learned a thing or two helping investors see a buy from a sell. Knowledge it shares openly in its website's Client Blueprint is a recipe for pretty much every step of the mergers and acquisition process.