The stock market fell this morning, and then it rose this afternoon. This morning, people everywhere reported why it fell. This afternoon, those people flip-flopped like a giant slinky and pretended to report why it rose. I don't know why it fell or rose. Nor am I concerned either way. I'm a Fool.

Many people argued long and hard that Amazon (Nasdaq: AMZN), America Online (NYSE: AOL), and eBay (Nasdaq: EBAY) were grossly overvalued. A few years later, many of those same people began to argue that these were now good stocks. Their negative arguments were replaced by positive discourses. I don't know why. Herd mentality? How should I know? Better yet, why should I pay attention to the Wise opinions? I'm a Fool. I invest based on my own thoughts.

People write letters asking, "Should I buy everything that your portfolio owns now, or should I just buy some of the stocks that you own?" We don't know, and won't pretend to know. We're merely standing in the middle of our town square, surrounded by the community that includes all of us, and we're donning bright colors and jester caps, and we're investing according to how we believe is best for us. Meanwhile, we're hoping that all other Fools will invest however is best for them. From the start, Fooldom was created to make it easier for you to make your own decisions on any topic that the Fool covers, from stocks, to home buying, to taxes and debt.

I haven't looked closely at the stock market today. Will that matter one year from now? Maybe I won't look closely until April's earnings announcements. Or, maybe I'll wait an entire year before looking again, and instead I'll spend my time doing a Motley array of other activities: reading books, seeing films, exploring the Northeast, and exercising.

I own companies that I know very well. In fact, I know the long-term mission of each company in which I'm invested. A long-term mission is typically at least five years, and is usually ten years or longer. So, do I need to check on the status of these "missions" every day, week, or year? Well, only if I want to. I'm a Fool.

Being a Fool means trying to find better solutions to investing and to living in general. I am a mere Fool, so if the following observation seems trite, please forgive me. Here it is.

I have noticed that if you buy the leading company in an industry, many times you end up buying several of the related leading companies in that industry and in related industries, too. This serves to simplify your investment decisions even before you make them. Let's explain how this works.

If you're trying to decide between buying three companies in one industry, and if you can delineate which company is the leader -- or which one has the most promise to lead -- consider simply purchasing that leading company, even if you like companies two and three, too. Why? Because purchasing the leader may eventually get you invested in all or most of the other companies that you have considered.

For example, the Rule Breaker Portfolio bought America Online. Before too long, America Online bought another key leader in the industry, CompuServe. Later, AOL bought one of the first big names in Internet investing, Netscape. AOL also bought MovieFone, as well as a cool foreign company that provided instant messaging on the Internet. Actually, in the last six years AOL has literally bought several dozen companies that the Rule Breaker Port, as an "investor," may have been interested in -- and ended up "owning" without effort.

Amazon was this portfolio's best idea when it came to investing in online consumer commerce. Through Amazon, this portfolio has also obtained stakes in Drugstore.com, Pets.com, Gear.com, HomeGrocer, and, again, literally several other companies that it may have been interested in buying. Through Amazon, the Rule Breaker Port was also able to buy the leading online book sellers in Germany and the United Kingdom. (Sites that were then turned into Amazon sites.) Likewise, through eBay the Breaker Port has bought the leading auction site in Germany and has taken investment stakes in a leading online automobile seller and several other auction companies. Thank you, eBay. (By the way, nothing new accounted for today's 13% gain, but the stock moved a little closer to a big-picture, think-large, 10-year goal.)

Finally, through our Starbucks investment, we've bought the leading coffee chain in the United Kingdom, the Seattle Coffee Company. This was a good company, but private, so we couldn't have bought it any other way. Thank you, Starbucks.

This portfolio is gaining new stakes in many leading companies around the world without paying any trading commissions and without having to conduct the trades. Simply put, that's extremely Foolish. You know, come to think of it, I've never heard any stockbroker suggest this type of "accumulate by investing in companies that dominate" investing method. Maybe because this way of investing doesn't lead to high trading commissions -- commissions that suit the Wise very well. Being Fools, we're not well-suited for such commissions. I don't imagine that you are, either, Fool.

Tomorrow, we aim to touch on America Online and Excite@Home, two stocks that are slip-sliding through the year like two children sharing a round, red sled on a snowy hill.

To talk Foolishness right now, visit the Rule Breaker discussion boards linked below. Fool on down!

-- Jeff Fischer, TMF Jeff on the boards.