As an editor and writer at The Motley Fool, I encounter a lot of brilliant investing ideas. Sometimes I notice them immediately and profit. Sometimes it takes me years of hindsight and regret to finally recognize them.

I tell you this because the brilliant ideas can hide, but the truly, magnificently stupid ideas can't. They announce themselves with an unironic roar.

I came across one especially stupid Wall Street investing idea recently that I want to tell you about. I don't want to ruin the surprise, but it smacks of shortsightedness and desperation. And because others' stupidity isn't truly useful unless we can profit from it, I'll also name seven stock ideas to take advantage of the less bright on Wall Street.

A bad idea in 140 characters or less
First, some background.

For those unfamiliar with Twitter, it's the social networking site that allows users to post their thoughts. The catch is that you have to do it in 140 characters or less. (For context, that last sentence was 62 characters long).

You can follow the half-baked thoughts of your favorite athlete, get real-time updates on your friend's latest caramel macchiato break, and read the latest Justin Bieber update.

All reasonable (and free) wastes of time. But now Wall Street has an idea of what to do with all the "data" that's floating around Twitter...

Wall Street's latest money-making scheme
Long story short, per a USA Today article, there's a study out there that "claims an 87% accuracy rate in using Twitter mood measurements to predict Dow stock prices three to four days later."

In other words, by parsing the millions of smiley faces, LOLs, and idle chatter posts on Twitter, computer programs can determine the mood of the market. And, more importantly, it can translate that into near-term stock predictions.

Supposedly, it's gained enough traction that "online surveillance of social-networking sites is emerging as a must-have tool for hedge funds, big banks, high-frequency traders and black-box investment firms that run money via computer programs."

Short-term trades with a purported 87% accuracy rate may sound tempting to you. But the past few years should be a stark reminder that not everything Wall Street does is smart (or money-making).

Why you need to run away ... fast
Let's set aside the taxes and commissions that kill the returns of short-term strategies. We can even set aside the fact that the study only covered nine months of data. Let's take a step back and look at the big picture.

Data is something we don't lack today. The mistake many investors make is thinking "one more data point can't hurt." Actually, it can. To make money in today's market, it's imperative to focus on the numbers that matter. Otherwise, we get lost in the minutiae.

Factoring in the emotions of a 13-year-old whose favorite American Idol contestant got booted off may be Wall Street's latest tool, but I'll stick with the truly meaningful data points. The ones that help us determine the price we're paying now and the profitable growth we can expect in the future. You know, quaint metrics like a company's sales, margins, growth rates, and price multiples.

7 stocks some idiots on Wall Street are missing
Focusing on finding companies that can win in the long term (years and decades), and buying them at good prices beats the heck out of jumping on the latest Wall Street investing fad. The former is how the great investors of the past have succeeded. And it's how the investing legends of tomorrow are doing it today.

If you're looking for stock ideas built for the long term, I've put together a list of seven companies that (1) have the potential to be great companies (if they aren't already) and (2) are small enough to grow.  

I've listed their market caps as well as a Twitter-friendly blurb next to each one. Check out the table and then I'll tell you how to use it.

Company

Current Market Cap

Long-term Story in 140 Characters or Less

Chipotle (NYSE: CMG)

$8.7 billion

I can't name another restaurant concept in Chipotle's space that engenders such broad-reaching fandom.

Tempur-Pedic (NYSE: TPX)

$4.4 billion

An innovative, high-end bedding company whose 50% gross margins make "putting your money under a mattress" a tempting option.

Morningstar (Nasdaq: MORN)

$3.0 billion

This article is about the proliferation of useless financial data. Morningstar provides the opposite.

Buffalo Wild Wings (Nasdaq: BWLD)

$1.1 billion

A debt-free restaurant concept that has achieved 23% sales growth and 32% EPS growth over the last five years.

Whole Foods (Nasdaq: WFM)

$10.7 billion

Supermarket chain that's riding the organic food trend with a focus on "conscious capitalism."

Rosetta Stone (NYSE: RST)

$0.3 billion

As we get more global, Rosetta Stone's learning software seeks to bridge the language barriers.

Intuitive Surgical (Nasdaq: ISRG)

$13.7 billion

As health care strives to get both cheaper and better while our population ages, robotic surgery has a tantalizing opportunity.

Sources: Yahoo! Finance and Capital IQ, a division of Standard & Poor's.

These companies rank among my favorite growth stories in the market. But I haven't bought shares in all of them yet. Here's why. Unlike those mining Twitter for investing ideas, I believe the big money is made by buying great companies at cheap prices and then holding for the long term. Or until some Twitter algorithm or future fad causes the market to overvalue the company.

So ignore the short-term noise, focus on finding great companies, and prey on some Wall Street idiots. And if you've got the appetite for one more stock idea, click here for our free report: "The Only Energy Stock You'll Ever Need." Hint: It's less than a tenth of the size of ExxonMobil.