President Trump's Twitter account got taken down by a rogue Twitter employee, and that's a big deal.

Here's why you should care: A handful of tech companies have power and influence as editorial gatekeepers and amplifiers. That power is growing and, increasingly, it's coming under scrutiny.

This week, executives from Twitter (TWTR), Facebook (FB) and Google (GOOG) were grilled on Capitol Hill. The topic at hand: Were the platforms weaponized by a hostile nation to affect the 2016 presidential election?

And then, while we're asking if tech companies have too much power, an employee at one of those companies was able to take the President's Twitter microphone away.

Trump's account only disappeared for 11 minutes. But it was a telling moment and has become part of the conversation about tech companies and their uncomfortable (and seemingly uncontrollable) role as gatekeepers.

Some lawmakers -- not to mention the public -- believe the companies aren't always just neutral platforms, and that they are not transparent enough about how they work and the decisions they make.

Related: How did this happen? 3 questions for Twitter after it deleted Trump's account

A Twitter employee with the power to silence the president may be an extreme example, but every day the company makes decisions on content.

The gatekeepers are increasingly being asked to explain those decisions.

Internally, Twitter is scrambling to figure out what happened with @RealDonaldTrump on Thursday night. The company will probably add new safeguards so fewer employees can access an account like Trump's going forward, but it's a moment worth looking at.

On Thursday, Twitter (TWTR) CEO Jack Dorsey sent two separate emails to employees that were obtained by CNN. "We are working to understand what happened and will share more as we know more. We are taking steps to make sure this can't happen again," he wrote in one.

No matter what steps they take in the immediate aftermath of this, though, the fundamental questions will remain: How much power should these companies have over speech? And are they able to control the platforms they've built?

One Twitter employee with whom CNN spoke expressed frustration that the president could tweet about North Korea in a way that potentially increases the likelihood of hostilities -- which could be interpreted as inciting violence, a violation of Twitter's terms of service -- and that Twitter would do nothing about it.

But another employee told CNN that, from a policy perspective, Trump hasn't violated the rules of Twitter and won't get kicked off it -- at least not by someone who isn't a rogue employee.

"Twitter's core job is to keep people informed, he's held to the same rules as everyone else," this employee said.

Related: Conservatives in Silicon Valley speak in shadows

Tough questions like what Twitter should do about Trump's use of the service are emblematic of an era in which decisions made behind closed doors in Silicon Valley are perceived as political -- and often do have a direct effect on politics, even if that's not the intention.

Being the referee of free speech is difficult, and the stakes are high.

"I think it is really risky if you have a group of essentially 10 tech CEOs, that if you somehow offend all 10 of them, that you can effectively not be on the internet anymore," Cloudflare CEO Matthew Prince told CNN recently, referring to his own decision to kick The Daily Stormer, a neo-Nazi site, off his platform.

Trump has been a divisive president, but he didn't have to bother all 10 tech CEOs to lose his spot on one of their platforms. Twitter had enabled an employee to make that decision instead.

It was for only 11 minutes, but it matters because it shows that even the president isn't immune.

"We have a lot more work to do," Dorsey said in his second email, thanking employees for trying to get to the bottom of Twitter's latest drama.