SUMMARY：
Concernsthat teenagers could be bored with Facebook
CONTENT：
David Ebersman, Facebook"s chief financial officer, saidthere was a lack of reliable data about the number of teens on the site, asthey were less likely to be honest about their age. Attempting to assuage concerns about the lack of growth among teen users, he said: "We remain close to fully penetrated among teens in the US."
However, he also warned that growth in the number of adverts in the newsfeed, which had been a "meaningful driver of revenue", would not continue at the samerate in the future. Mobile revenue rose in the third quarter to reach 49 percent of total advertising revenue – up from just 14 per cent in the same quarter last year.
Mobile monthly active users were 45 percent higher than the year before at 874m, and more than 500m people used Facebook on their mobile devices each day on average during September.
KEYWORDS:
David Ebersman：戴维·埃博斯曼
newsfeed：信息流
参考译文1：
Facebook的青少年用户数量增长缓慢，为了减轻公司股东对此的忧虑，其首席财务官戴维·埃博斯曼表示， facebook用户中青少年人数的统计数据缺乏可靠性，因为用户大多不会登记真实年龄。 “我们仍将不遗余力的在美国青少年中推广使用facebook”
然而，戴维·埃博斯曼也不无担心的表示，信息流广告一度为公司创造了可观的收入，但是今后信息流广告数量的增幅将不容乐观。第三季度中移动业务收入占全部广告收入的49%-与去年同期14%的比例相比有所提高。
移动客户端的月活跃用户达到了8.74亿，与去年相比增长了45%。九月份，平均每天有超过5亿人在使用facebook移动客户端。
参考译文2：
Facebook首席财务官大卫·伊伯斯曼说，由于Facebook的青少年用户在账号的个人信息中不愿意填写他们的真实年龄，所以这部分用户的数量还缺少可靠的数据。为了减轻青少年用户数量增长缓慢的忧虑，他说：“我们仍将继续在美国青少年中全面渗透。”
然而，他也警告说，信息流方面的广告数量增长一直是促进公司收入的强大动力，但是在将来不会再如此了。第三季度的移动收入增长到占整个广告收入的49%，相比去年同期的14%来说是增长了。
每月活跃用户相比去年的8.74亿人增长了45%。九月份，每天在移动设备上使用facebook的人超过了5亿。
