Twitter has long had a trolling and harassment issue, and its CEO isn’t immune to it. CEO Jack Dorsey said he has been harassed on Twitter, but he has not blocked any users himself, he told NBC “Today” show host Matt Lauer on Friday.

“I can block people. I’ve never blocked anyone," Dorsey said. 

Picking from crowd-sourced questions on Twitter, Lauer had asked Dorsey about his company’s stance and activity on censorship, which led to a conversation on blocking.

“Does Twitter censor?” Lauer said.

“Absolutely not,” Dorsey said. “It’s our job to make sure they see the most important things.”

That isn’t completely true, as Dorsey noted. Twitter’s terms of service forbid users from promoting violence, for example. Twitter has proactively looked for ISIS-related accounts to shut down. Since mid-2015 to February, Twitter has suspended more than 125,000 accounts for promoting terrorist acts, the company revealed last month.

Per this policy, Twitter will respond to user reports of harassment and also look for similar accounts that may be violating the terms of service.

But other than those actions by the company, Dorsey encouraged users to take control of their own feeds. “There are tweets that promote violence that are against our terms of service … who decides the difference between criticism and hate? You can decide who you want to follow,” he told Lauer.

Lauer also asked him about celebrities use of Twitter. “Any time she sends a tweet it’s great,” Dorsey said in regards to Kim Kardashian. “As a microphone it’s at its best,” he said about Donald Trump.

Dorsey appeared on the “Today” in celebration of his company’s 10th birthday on Monday. On March 21, 2006, Dorsey sent the first tweet:

Since then his company has seen highs and lows, from steady user growth that led it to successfully open on the public market to the stock crashing down and growth stagnating.

Dorsey also has been balancing two jobs, as CEO of Twitter and CEO of mobile payment service company Square Inc. It’s a balancing role Steve Jobs also endured, to which Lauer asked if he likes the comparison. “He was an original. I’m a student of his work,” Dorsey said.

Dorsey’s seen the headlines like “The End of Twitter” and said he’s confident in the future. “We’ll be here on the 20th, on the 30th. It’s a fundamental service. We have a lot of heart at the company,” Dorsey said.