As the electronic trading of stocks continues to grow in popularity, brick-and-mortar exchanges like the New York Stock Exchange are becoming increasingly anachronistic. As if to underscore how some fledgling electronic exchanges are disrupting the traditional Wall Street way of doing business, some money managers are calling Liquidnet, an e-marketplace that allows institutional investors to trade large blocks of stock anonymously, a "Napster for stocks." According to one equity trader, "Liquidnet was the first to bring the liquidity to you rather than us carving up our order flow and sending it out. The beauty is anonymity, lower rates than full-service brokers, and it comes to you--versus you having to go out.”

The valuation of Liquidnet is staggering: based on a recent financing deal, the three-year-old company is already valued at $1.8 billion. By way of comparison, the NYSE is worth about $1.3 billion, Nasdaq is worth $794 million and Archipelago is worth about $873 million.