SAN FRANCISCO • Twitter's streak of executive turnover is continuing.

Its chief technology officer Adam Messinger tweeted on Tuesday that he was leaving the company. His departure follows that of chief operating officer Adam Bain, who exited last month. Other top product, engineering and media team leaders have also left this year.

"After five years I've decided to leave Twitter and take some time off," Mr Messinger said in the post.

His exit once again raises questions about the stability of Twitter's executive bench. The social media company has been struggling to attract more users to its 140-character message service, while trying to figure out how to improve revenue growth.

In recent months, Twitter has flirted with selling itself to suitors such as Salesforce.com, but discussions ended with no resolution. The company has since been in cost-cutting mode, reducing its staff and shedding some of its businesses.

One of the biggest blows to Twitter was the loss of Mr Bain, who was an unofficial internal mascot beloved by many employees for his cheerful demeanour and his cheerleading of the company.

Chief financial officer Anthony Noto took over the chief operating officer position, and Twitter is searching for a new CFO.

Mr Messinger was not the only executive to leave Twitter this week. Mr Josh McFarland, a vice-president of product, said he was departing to join venture capital firm Greylock Partners.

Mr McFarland, who oversaw much of advertising product development, joined Twitter in April last year when it acquired his company, the digital advertising platform TellApart, for about US$500 million (about S$720 million).

Mr McFarland was a rising star, respected for being decisive and willing to have hard conversations, former Twitter employees said.

Mr Messinger joined Twitter in 2011 from Oracle. He began as a vice-president working on engineering infrastructure, and later moved to overseeing application development. He became chief technology officer in 2013.

Over the past year, Mr Messinger had been given more responsibilities by chief executive Jack Dorsey.

After some executive reshuffling, Mr Messinger gained oversight of the engineering organisation, as well as product development and design. He helped decide on Twitter's new product leader, Mr Keith Coleman, a former Google employee who had worked on that company's Gmail and chat apps.

Mr Messinger was awarded 1.25 million restricted stock units for his additional duties. Twitter's heads of product, design and engineering will now report directly to Mr Dorsey. Mr Edward Ho, a vice-president of engineering, will take over Mr Messinger's engineering duties.

"I'll be working even closer with our engineering and design teams to ensure we continue to be the fastest and best service to show what's happening in the world," Mr Dorsey said in a statement.

Mr Messinger's supporters lauded what they described as his cerebral approach, but he also had detractors who said he was indecisive and sometimes did not take enough concrete steps to make changes happen, according to three former Twitter employees.

NYTIMES