SAN FRANCISCO — Dick Costolo,Twitter's embattled chief executive, is stepping down, the company said Thursday.
旧金山——根据Twitter公司周四公布的消息，陷入困境的公司首席执行官迪克·科斯特罗(Dick Costolo)即将卸任。
Jack Dorsey, the company's co-founder and chairman, will serve as interim chief executive while the board searches for a permanent successor.
在董事会寻找永久接班人期间，Twitter的联合创始人、董事长杰克·多尔西(Jack Dorsey)将担任临时首席执行官。
The change is effective July 1. Twitter shares were up more than 7 percent in after-hours trading immediately afterthe news was announced.
这一变动将于7月1日生效。消息宣布之后，Twitter在盘后交易中的股价立即上涨了逾7%。

Since Twitter's debut as a public company in 2013, Costolo has repeatedly disappointed Wall Street as the company struggled to attract new users, refine its products and develop new forms of advertising.
自2013年Twitter上市以来，由于公司在吸引新用户、完善产品和开发新的广告形式方面困难重重，科斯特罗多次让华尔街失望。
Costolo's departure is likely to renew speculation Twitter is an acquisition target for the handful of tech giants that could afford the company, which currently has a market valuation topping $24 billion.
科斯特罗的离任很可能会再次引起外界的猜测：Twitter将成为有能力收购它的少数几家科技业巨头的猎物。公司目前的市值超过了240亿美元（约合1500亿元人民币）。
“The situation at Twitter must be much worse than it appears, as replacing the CEO is such a big step,” said Brian Blau, an analyst with Gartner. “Twitter's problems are clearly not over, and while Jack Dorsey knows Twitter well, they really should bring in some outside perspective as most of their strategies so far are not working out so well.”
“Twitter的情况肯定比表面看来糟糕得多，因为更换CEO是个重大举措，”高德纳公司(Gartner)的分析师布莱恩·布劳(Brian Blau)说。“Twitter的问题明显没有结束。尽管杰克·多尔西非常了解Twitter，但他们的确应该引进一些外部视角，因为他们大多数的策略目前表现不佳。”
Twitter accounted for 3.6 percent of the $19.2 billion mobile Internet ad market in the United States last year, according to eMarketer, while Facebook held an 18.5 percent share and Google dominated with 36.9 percent.
根据研究公司eMarketer公布的数据，去年，Twitter在规模达192亿美元的美国移动互联网广告市场中占据3.6%的份额，而Facebook占18.5%，谷歌(Google)更是以36.9%的份额独占榜首。
Pressure on Costolo grew in recent weeks after Chris Sacca, an early Twitter investor,went public with an 8,500-word analysiscalling for a much deeper rethinking of Twitter's service.
Twitter的早期投资者克里斯·萨卡(Chris Sacca)早前公布了一份长达8500字的措辞严厉的分析报告，要求对Twitter的服务重新进行更深入的思考。这使得科斯特罗最近几周面临越来越大的压力。
“I am tremendously proud of the Twitter team and all that the team has accomplished together during my six years with the company,” Costolo said in a statement Thursday. “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.”
“对于Twitter团队，以及团队在过去六年我服务于公司期间取得的成就，我感到十分自豪，”科斯特罗周四发表声明称。“我们拥有配合默契的卓越领导者，还有体现我们目标及首要任务的清晰策略。在这个过渡时期，杰克·多尔西是领导Twitter的最佳人选。”
Twitter, founded in 2006, has never been known for its stable management. Costolo became chief executive in October 2010 as part of a boardroom coup against Evan Williams, Twitter's co-founder and then-chief executive.
Twitter创立于2006年，其管理层一向欠缺稳定性。2010年10月，在针对Twitter联合创始人、时任首席执行官埃文·威廉姆斯(Evan Williams)的董事会政变中，科斯特罗成为首席执行官。
This is the second rise to Twitter's top ranks for Dorsey. After being ousted as chief executive and replaced by Williams in 2008, Dorsey returned to Twitter as executive chairman in 2011 when Williams was pushed out of the chief executive's office, replaced by Costolo.
这一回将是多尔西第二次升任Twitter的最高领导人。在2008年被威廉姆斯取代首席执行官职位以后，多尔西于2011年科斯特罗将威廉姆斯赶下台后回到Twitter担任常务董事长。