In a series of tweets, of course, Adam Bain said Wednesday that he's leaving Twitter.
Bain, the company's chief operating officer, said he's excited to do something "totally different and new outside the company" but didn't give specifics.
Twitter's chief financial officer, Anthony Noto, has been named COO effective immediately, Twitter said in a statement Wednesday.
Bain's departure comes nearly two weeks after the company announced a new round of layoffs, which had been widely rumored, including in the sales division he oversaw. Bain is joining a list of several key figures, such as product head Kevin Weil, who left Twitter this year.
The loss also comes as Twitter continues to suffer fallout from its inability to attract new users, said Gartner analyst Brian Blau. "Today's departure of Adam Bain is yet another example of their struggles to retain talent and turn the company around despite their efforts to do so since Jack Dorsey returned as CEO in mid-2015," he said.
Perhaps the social network's current direction may not suit Bain well, said Forrester analyst Erna Alfred Liousas.
"Twitter's new path may represent something that Adam isn't comfortable with, or perhaps it is another opportunity for yet another perspective to emerge -- potentially guiding this iteration of Twitter through new waters," she said.
Bain took on the role of COO last year and previously served as Twitter's president of global revenue and partnerships. Prior to Twitter, Bain was a chief technology officer at Fox Interactive Media, where he helped lead the company's acquisition of the once uber-popular MySpace.
In his tweets Wednesday, Bain applauded the social network and thanked co-founders Dorsey, Biz Stone and Evan Williams, as well as Costolo. Twitter's top brass offered up their own well wishes for Bain, also in tweets.
The social network has struggled in recent years as user growth has flat-lined, infuriating Wall Street and efforts to transform the platform into a live-streaming hub, including airing Thursday night NFL games, are yielding mixed results.
First published November 9 at 3:26 p.m. PT.
Update, 6:50 p.m. PT: Added comments from analysts and background information.