For years we've been hearing about crowd mentality when it comes to investing. People hear about trends, then follow them, often causing runs on the market or economic idiosyncrasies. Now, one company in Great Britain is looking to harness crowd mentality using the Web to allow investors to make more savvy investment decisions.

Covestor, a Web startup with offices in London and New York, allows people to manage their money by following the lead of other investors -- successful investors. Using a Web-based paradigm, an investor can take a look at what somebody else is trading, then duplicate that person's trades.

Although this might strike you at first as being risky, once you get into the details, it seems perfectly natural. If John is a savvy investor in tech stocks, and if I want to get into tech stocks, it's only natural for me to want to see what John is doing. It's also natural for me to want to see how John's real world portfolio is doing so I don't fall prey to John's phony bravado about his stock picking prowess.

Covestor allows that to happen, without putting John's privacy at risk. Using technology from Yodlee, a company that provides similar services to banks and bank customers, Covestor makes John's portfolio available so you and I can see his actual trades. Yet it unveils only the trades and percentages of his portfolio that are affected -- not his actual account information. And it currently cannot execute trades in his accounts. John can even decide to remain anonymous.

To start up, John enters his brokerage accounts into the system and the system establishes electronic communications with those accounts. Whenever a trade is made, Covestor gets certain information about the trade (such as the stocks from which and into which John is trading); and it tracks John's performance.

You and I can find an appropriate savvy investor by looking at Covestor's scoreboards to see who trades the way we want to trade and who is making money. We can then follow them in our own accounts. In theory, we get a better return on our investments because we get better advice. John, in return, gets bragging rights -- if he doesn't choose to be anonymous.

According to Simon Veingard, one of Covestor's three founders, the service is able to tap into the expertise of investors who can make decisions as well as or better than professional money fund managers -- without the typical cost of the well-paid money fund manager. So the user can get the returns without the cost.

Since June of 2007, he's already attracted more than 10,000 investors and says the total value of their trading assets represent well in excess of $100 million.

Although not yet ready, he's hoping to soon be able to execute trades on behalf of those investors, thereby adding a profit incentive for his company and for the investors who are willing to let others tap into their portfolios. He'll do that by taking a small percentage of those trades as fees -- supposedly a much smaller percentage than the fees taken by professionally managed funds -- and split them with the investors whose portfolios are being tracked.

The bottom line should be a win for everybody. Trackers get better returns; those being tracked earn fees like the professionals; and Covestor shares in the profit.

Despite my assertion that a logical step would be to create indexes based on the success of his biggest winners, Mr. Veingard says that's not in the cards. He'd rather defer to the individual investors as experts.