Twitter's chief operating officer Ali Rowghani announced today that he would be stepping down from his day-to-day role with the company and moving into an "advisory" role. Rowghani had been with Twitter for four years, coming over from Pixar, where he served as chief financial officer. His departure highlights the company's struggles with user growth and engagement, as well as its lack of hit new products, two areas that Rowghani helped to oversee. News of the executive shakeup was first reported by Recode.

Rowghani had been highly touted in the press, including in a Wall Street Journal article that referred to him as Twitter's "Mr. Fix-It" and a "co-CEO" alongside Dick Costolo. But the young company has struggled in recent months, with its stock price far off its recent highs and below the $45 mark where it ended its first day of trading. Investors' primary concern has been a slowdown in user growth and drops in engagement.

Twitter has also failed to launch any hit products to compliment its core service. The short-form video service Vine has found a sizable user base, but is still dwarfed by competitors like Instagram, which has added video. Vine has also failed to find the same kind of rapid growth as younger apps like Snapchat, which recently added video chat as well. Its other solo app, Twitter #Music, was shut down in March. The company did report improved financials in its last quarter, doubling its revenues year over year. So far there is no indication Twitter plans to find a replacement for Rowghani.