In a big news day for Twitter, the company has announced that CEO Dick Costolo will be stepping down as CEO, effective July 1, with co-founder Jack Dorsey stepping in as interim CEO.

The news comes after much scrutiny for the CEO, with Twitter stocks recently taking somewhat of a dive and the battle against online harassment becoming an increasingly important issue.

"I am tremendously proud of the Twitter team and all that the team has accomplished together during my six years with the Company," said Costolo in a statement. "We have great leaders who work well together and a clear strategy that informs our objectives and priorities. There is no one better than Jack Dorsey to lead Twitter during this transition."

Shareholders have expressed little faith in Costolo since he took the reigns at Twitter in 2010. In fact, Twitter stocks jumped eight percent after the announcement of his resignation as CEO. Despite this, Costolo was well-respected and liked by Twitter employees and the public, with his stance against harassment on the company being an important factor.

Costolo cited wanting to move on from the company as one of the main reasons for his stepping down. The news comes only a few weeks after Costolo said that his vision for Twitter and the vision of the board was the same.

The company also announced that, starting in July, it would be removing the 140-character limit for direct messages, allowing the social media network to be a far more effective private communication tool.

"We've done a lot to improve Direct Messages over the past year and have much more exciting work on the horizon," said the company in a blog post. "One change coming in July that we want to make you aware of now (and first!) is the removal of the 140 character limit in Direct Messages. In order to make this change as seamless as possible for you we've included some recommendations below to ensure all your applications and services can handle these longer format messages before we flip the switch."

Twitter is fast changing, and for good reason. The company is struggling to find ways to monetize its platform and has even been the subject of acquisition rumors, with some suggesting that Google has been in talks with the company. Not only that, but the company has also seen a slowing of user adoption. A new CEO will likely bring a breath of fresh air to the company and how it is run.