For today's S&P addition let's walk down memory lane, shall we?

For today's S&P addition let's walk down memory lane, shall we?

On December 7, 1999 Yahoo was added to the S&P 500 with enormous fanfare. The company was the "Google" of its era, as judged by Wall Street popularity. At the time, entering the S&P 500 was considered to be one of the highest honors a stock could receive. It was a stamp of approval that a business was large and stable enough to be included in the most widely fund-followed index in the world.

On that single day, Yahoo soared from $286 to $353 per share- for an eye-popping 23 percent gain. An amazing 265 million shares were traded, for a total dollar volume of around 90 billion bucks. Here's the historical data if you don't believe me. Never before or since has a company traded that much moolah in one day on any US market.

Unfortunately for everyone who thought the S&P inclusion was going to legitimize their investment, what actually happened is that all the growth funds and hedge funds and brokerages of the world took advantage of the incredible amounts of "dumb money" that were forced to buy on the S&P inclusion. They happily unloaded their overpriced shares into the rabid hands of wide-eyed investors everywhere.

And they all didn't live happily ever after- except for those who took the money and ran when the S&P came a knockin'.

One year later on December 7, 2000 Yahoo was trading at 31 dollars per share. There was a 2:1 split a bit earlier, so let's call it 62 dollars a share. Yahoo had lost 83 percent of its value.

But don't worry, I'm sure this time it's different- we've reached a permanently high plateau. There's no way investors could ever make the same mistake again. And again. And again.