Dark pools sound shadowy and mysterious. They’re not for swimming. They’re for buying and selling stock anonymously, away from the peering eyes of other participants in the capital markets. And over the last several years, the use of dark pools has risen substantially.

Related: Don’t Trust the Market? You’re Not Alone, For Good Reason

In fact, the portion of stock trading taking place away from public exchanges – in places including dark pools – has recently hit new highs. It’s amounted to close to 40% on some days this year, up from an average of 16% five years ago, according to Rosenblatt Securities.

So as you watch the stock market go higher, should you be worried about the increase in trading going on in the shadows?

Maybe not if you consider why dark pools exist in the first place.

Related: ‘Flash Crash’ Was a Warm-Up: Computerized Trading Threatens Global Financial System, Author Says

“The original purpose of dark pools was to create an anonymous environment where large

The U.S. economy may be hitting another "spring swoon," the same way it has for the past several years.

A slowdown from the economy's already slow rate of growth would not be surprising given the impact of the "sequester" and tax increases that went into effect earlier this year. These moves trimmed government spending across the board and increased taxes on most Americans

Not surprisingly, the sluggish economy has led to increased pessimism among American consumers. According to a new Associated Press-GfK poll, only one in four Americans expects their financial situation to improve over the next year. And only 46% of Americans now approve of President Barack Obama's handling of the economy.

The government certainly bears some responsibility for the state of the economy. The sequester, especially, was widely viewed as bad policy, and many economists thought it was not only unnecessary but would hurt the economy.

But much of the blame for our weak economy also lies with the private