One of the first rules I learned as a consultant was to avoid people you barely know who wanted to take you to lunch. Such meals invariably were suggested by people who want to tap into your knowledge and expertise without paying for it. Worst of all, you always left the meal hungry, because you spent the whole time answering a non-stop stream of questions.

These lunchtime "brains drains" have been largely replaced by so-called "expert networks," online marketplaces that allow consultants and other experts to sell their knowledge on an hourly basis to those who want a crash course on a specific industry, trend, technology or company. These expert networks have long been popular with private equity firms, hedge funds and other investors. It's a fast and efficient way for investors to check out a proposed investment. It's also a way to develop ideas and insights that gives an investor an edge.

If you've been following the recent spate of insider trading indictments, you'll note that a number of them involve expert networks that allegedly went over the edge, moving beyond providing ideas and insights into providing insider information.

So if an expert network has crossed the line into providing insider information, shut 'em down and move on, right? Yes, except for one thing: the definition of insider information has always been a bit murky, and seems poised to get murkier, so much so that data providers may feel some of the fallout. That's because there are those who contend that you can create non-public information (the stuff of insider information) out of publicly available information. Information alchemy, or so it would seem.

Yes, the public data most of us sell, often for purposes of business and competitive intelligence, when combined with other public data can, through some type of information alchemy, become non-public data that is subject to insider information rules. Even scarier, nobody seems to know exactly when that line gets crossed.

As I understand it, data providers need not worry directly, because the information we individually provide is clearly public, and only part of the picture being assembled, the "mosaic" in Wall Street parlance. However, this heightened scrutiny puts an uncomfortable spotlight on the expert networks (for example,MedaCorp, the first expert network in the healthcare area, announced this morning it will close).

Even more worrisome, we could see a chilling effect on how extensively and aggressively investors acquire data to build their mosaics, and that could have a bottom line impact for many data publishers. As investors seek to turn obscure bits of data into gold, regulators seem poised to turn that gold into dross.