The Nasdaq "hunters" have bagged six prey, but have not yet filled their limit. In a few weeks, several companies that now list on the New York Stock Exchange will also be found on the Nasdaq, under their same three-letter symbols.

The six -- Apache Corp. (NYSE:APA), Cadence Design Systems (NYSE:CDN), Charles Schwab (NYSE:SCH), Countrywide Financial (NYSE:CFC), Hewlett-Packard (NYSE:HPQ), and Walgreen (NYSE:WAG) -- are among many NYSEers that have been wooed by the Nasdaq in recent months. In fact, the exchange's president and CEO, Bob Greifeld, told The Wall Street Journal that he has divided some of his managers into "hunters" and "farmers." The former try to lure defectors from the NYSE, while the latter cultivate relationships with existing Nasdaq members.

Greifeld had hoped to convince many companies to leave the NYSE altogether, but that has yet to happen.

It's clear why Nasdaq wants to grow more robust, but what's in it for the companies? Schwab CEO David Pottruck says he hopes the dual listing will result in "innovative applications of technology, heightened transparency, and improved trading outcomes for all investors."

We think we speak for all investors in asking, what in the heck does he mean?

There's probably little impact here for individual investors. It is, however, likely another shot across NYSE's bow in protest of its specialist trading system. Unlike the computer-run Nasdaq, the Big Board still employs floor traders who match up buyers and sellers. The NYSE defends the practice, claiming it usually gives traders better prices. But many see it as an inefficient system, with too many possibilities for wrongdoing.

Another aspect to think about is the possibility of a change in some of the stock indexes. Could some of the dual-exchange companies make it into the Nasdaq 100, for instance? The exchange has not yet commented.

In the meantime, investors in these dual-listed stocks can get ready to check prices on two exchanges before buying and selling.