Last Thursday, the stock trading firm Robinhood Markets inadvertently said it would block its users from purchasing the shares of Best Buy Co., traded under the stock ticker symbol of BBY.
There was no reason to block it, as Best Buy's stock is nothing like the spectacularly volatile "meme stocks" of fading retailer GameStop and cinema operator AMC Entertainment Holdings.
Apparently a Robinhood staffer had meant to type BBBY, the ticker symbol for the stock of Bed Bath & Beyond Inc. It was quickly corrected, an honest mistake.
I made one last week, too, a humbling error about the value of Medtronic's interest in a new deal. Mistakes happen.
That's one way to explain how the stock price of AMC Networks went from the $40s on Jan. 22 to more than $70 last week to settle back in the $40s. Some traders eager to put a pop into AMC Entertainment must have been buying the wrong AMC.
It sure looks like a mistake to bid up the shares of struggling retailer GameStop to the point the whole company reached a value of more than $30 billion in the market, too. But it's simply not fair to dismiss what the industry calls retail investors behind the massive rally as clueless novices.
One objective was buying enough options and stock to create a surging stock price that hammered hedge funds like Melvin Capital Management that had established trading positions expecting GameStop stock to decline. Spotting that vulnerability took plenty of sophistication.
We may yet find out that much of the action with GameStop, AMC and the others over the last month was the work of hedge funds and other pros. But at the moment, it's a tale of small investors scaling the castle walls to topple the arrogant princes of Wall Street.
There are big issues to try to grasp here, including the lingering resentment that the wrongdoers of the 2008 financial crisis largely escaped punishment. Millennials also seem really sick of being lectured by their elders who had the good fortune to reach adulthood when it was easier to get ahead.
But this is not a "this time it's really different" moment in the market. Those don't come around very often.
The herd now speculating in stocks, gathering online in places such as Reddit, looks like the herds of past booms.
The principal action that shot GameStop stock into the stratosphere was a variation of something called a short squeeze, and those have been going on for a long time, too. A classic of the form took place in the Twin Cities more than 20 years ago in the stock of the company K-tel International Inc.
This once high-profile company, seller of the Veg-O-Matic and popular music compilations, announced in the spring of 1998 that it would start selling on the internet. The dot-com mania was gathering steam then, and this seemed like news.
Lots of investors didn't buy the bullish case, though, and a move to short K-tel began.
Now, short selling isn't necessarily a bad thing. While it can be done with stock options, short selling generally means borrowing shares investors don't own and selling them, then locking in a profit by buying back cheaper shares after the price sinks.
If the bulls keep buying, though, those short positions can get so costly at ever higher stock prices that the pain of getting squeezed forces the short seller to buy back the shares at a big loss. Of course, that creates another buyer in a market that already has more buyers than sellers.
On one particularly wild day that spring of 1998, trading volume in K-tel was 14 million shares, when there were fewer than 4 million shares outstanding and far fewer available to be traded.
The stock price spiked and almost touched $40 per share that spring from a low of just over $3 per share, although it didn't stay long at that lofty level.
The fun went out of trading Internet-related stocks when the air rushed out of the bubble 20 years ago. But for those who missed that go-go era, it really was a lot like what we've seen lately.
Instead of social media sites like Reddit, message boards found on then-new websites like Yahoo was where the enthusiastic traders chatted up their stocks at all hours.
There was also a lot of talk about how regular folks can beat those Wall Street pros. Investors excitedly piled into companies like computer-disk maker Iomega because they were investing in what they knew and liked, including Iomega's briefly popular Zip computer disk. It didn't end well, of course.
There was nothing back then quite like Robinhood, a stock-trading tool for smartphones that has the look of a video game. Whether it's a "gamified" financial app is a judgment call, but I have not found a transaction I can do on the U.S. Bank app that shoots confetti across the screen.
Robinhood is also "free," which only means users have no idea how much it's really costing them.
And back in the old days of the 1980s or 1990s bull markets, no one would have been able to click on a video of an unlikely internet celebrity like Dave Portnoy pulling three Scrabble tiles from a bag to pick the stock he's buying next.
But then as now there were complaints that enthusiasts on the internet must be manipulating the market. One of the priceless insights on just who is doing the manipulating also came from the dot-com era, and the oracle who saw it so clearly was just a kid.
As described by the writer Michael Lewis, a 15-year-old in suburban New Jersey named Jonathan Lebed had used an online broker, often from the high school library's computers, to quickly make a bundle buying and selling stocks and promoting some online. Then the Securities and Exchange Commission came knocking.
In a note the teenager wrote his own lawyer, it's clear he just didn't see what he could have done wrong.
"Whether it is analysts, brokers, advisers, internet traders, or the companies, everybody is manipulating the market," he wrote. "If it wasn't for everybody manipulating the market, there wouldn't be a stock market at all."