Facebook Inc. went public last month on its prospects for growth. But in some key areas, the social network's growth rates are already maturing.
凭借着公司未来的增长前景，Facebook上个月得以上市。但是在一些关键领域，这家社交网站的增长已经开始趋于饱和。
In particular, Facebook's user growth rate in the U.S. is slowing sharply. In April, U.S. unique visitors to the website increased to 158 million, up just 5% from a year earlier, according to research firm comScore Inc.
尤其需要指出的是，Facebook在美国的用户增长速度正在迅速放缓。据研究公司comScore Inc.的数据，Facebook在美国的用户数量4月份增长至1.58亿，这比一年前的水平仅增加了5%。
That was Facebook's lowest U.S. user growth rate since comScore began tracking the data in 2008 and was down from 24% growth in April 2011 and 89% in April 2010, comScore said.
comScore表示，自从该公司2008年追踪Facebook的数据以来，4月份是Facebook美国用户数增速最低的一个月。相比之下，2011年4月的同比增幅为24%，2010年4月为89%。
At the same time, the growth rate in the amount of time people spend on the social network -- otherwise known as engagement is also decelerating. In April, Facebook users spent more than six hours a month on the site, up 16% from a year earlier. But that compares with a 23% increase in 2011 and 57% in 2010, comScore found.

ReutersFacebook在美国用户数量的增长正在急剧放缓。与此同时，人们花在这家社交网站上的时间虽然还在增长，的增速也已下降。4月份，Facebook用户平均每月在该网站上花费的时间为6小时以上，较一年以前的水平提高了6%。不过comScore发现，相比之下，2011年同期的增幅为23%，2010年为57%。
In some ways, the slowdown is to be expected. Facebook has already grabbed 71% of all 221 million U.S. Internet users, according to comScore. At the same time, people are on Facebook longer than any other site. The more than six hours a month that people spend on the social network exceeds the over four hours a month they spend on all Google sites including YouTube, and the 3 1/2 hours they spend on Yahoo sites, comScore said.
从某种程度上讲，这些减速现象完全在意料之中。根据comScore的数据，美国2.21亿互联网用户中，已经有71%注册了Facebook。同时，人们在Facebook上花费的时间也比其他网站多。与Facebook每月6小时以上的水平相比，美国人每月花在包括YouTube在内所有谷歌网站上的时间为4个小时以上，而花在雅虎网站上的时间为三个半小时。
With such a dominant presence and so much time already spent on the site, "declining growth rates are a natural part of the growth cycle,"said comScore analyst Andrew Lipsman.
comScore的分析师利普斯曼(Andrew Lipsman)说，鉴于Facebook已经赢得了绝大多数的互联网用户，并且用户已经在其网站上花费了如此多的时间，增长速度的下降是其增长周期中一个必然阶段。
Still, the falling rates are significant given that Facebook has framed itself as a growth story to Wall Street.
尽管如此，考虑到Facebook已经向华尔街夸下海口，其增长速度的下降仍然非同小可。
When it went public last month, the Menlo Park, Calif, company commanded a valuation of more than $100 billion, partly because investors expect Facebook to grow at triple-digit and double-digit rates much like Google Inc. did after its 2004 initial public offering of stock. Yet Facebook's shares are off 29% since they priced at $38 ending at $27.10 on the Nasdaq Stock Market at 4 p.m. Friday and the company's market capitalization has sunk to $73.17 billion.
这家位于加州的公司上个月上市时的估值达到了1,000亿美元以上，其部分原因是投资者预计Facebook将实现三位数或两位数的增长，就像谷歌在2004年首次公开募股之后所经历的那样。然而自从以每股38美元的价格公开发行股票以来，Facebook的股价已经下跌了29%。上周五，Facebook在纳斯达克市场(Nasdaq Stock Market)的收盘价为每股27.10美元，公司的市值也下降到了731.7亿美元。
Indeed, comScore's numbers illustrate how little room there is left for Facebook to grow in the U.S., which is the most important and lucrative market for the social network's two revenue-paying constituencies: advertisers and developers.

事实上，comScore的数据表明Facebook在美国已经几乎没有继续增长的空间，而美国市场对于广告客户和程序开发者来说是最重要和最有利可图的市场，广告客户和程序开发商又是Facebook的两个主要收入来源。
Approximately 56% of Facebook's 2011 ad revenue of $3.1 billion came from the U.S. alone, according to the company's regulatory filings. "The U.S. is a dominant source of revenue for Facebook," said eMarketer analyst Debra Aho Williamson, who estimates that this year the nation will account for 51% of Facebook's revenue.
Facebook提交给监管机构的备案文件显示，该公司2011年获得的31亿美元广告收入中，大约56%来自美国。eMarketer的分析师威廉姆森(Debra Aho Williamson)说，美国是Facebook收入的最主要来源。他估计，Facebook今年的营收中将有51%来自美国。
Morningstar analyst Rick Summer said comparing Facebook's growth rates to Google's post-IPO might not be an apt analogy given that Google went public at an earlier stage of the Internet's development. "Google had the advantage of increases in ad pricing, increases in the number of Internet users and stealing market share from other Web properties," he said. By contrast, he said, "Facebook is already a dominant Web platform and they've got significant Internet penetration today. Ad pricing is clearly going to be where their growth is going to come from."
Alison Yin for The Wall Street Journal从某种程度上讲，这些减速现象完全在意料之中。根据comScore的数据，美国2.21亿互联网用户中，已经有71%注册了Facebook。图为上个月，Facebook加州门洛帕克办公园区中的员工。晨星公司(Morningstar)的分析师萨莫(Rick Summer)说，拿Facebook的增长率与谷歌上市后的增长率作对比可能并不合适，因为谷歌是在互联网发展的较早阶段进行IPO的。萨莫说，谷歌当时拥有诸如广告定价存在上涨空间、互联网用户数量正不断增长以及可从其它门户网站抢夺市场份额等优势。他说，相比之下，Facebook目前已是一个居主导地位的互联网平台，它的互联网渗透率已经很高。只有在拥有业务增长空间的地方，广告定价才有上涨空间。
Mr. Summer said he expects Facebook to be able to grow into its valuation over the long term. In the short term, however, he said the slowing user and engagement growth rates as well as slower ad-revenue growth are likely to pressure the stock for another year or two.
萨莫说，他认为长期来看Facebook有能力证明其估值名副其实。不过他也说，短期而言，用户数量和用户在网站上停留时间(以及广告收入)的增长放缓可能会让Facebook的股票再承受一到两年的压力。
Facebook still has growth sources. The comScore numbers don't take into account overseas markets and the mobile sector, which are categories where Facebook has room to expand. In its regulatory filings, the company has said it is experiencing substantial growth in countries such as India and Brazil, although ad rates in those countries are lower than in the U.S.
Facebook仍有增长点。comScore的数据不包括海外市场和手机上网用户方面的情况，而Facebook在这两个领域都有扩张空间。Facebook在递交给监管机构的备案文件中说，公司在印度和巴西等国的业务正迅速增长，不过这些国家的广告价格要低于美国。
Facebook is still experiencing growth in the use of its site on mobile phones. In March, the company said its monthly mobile usage world-wide rose to 488 million users from 425 million in December.
通过手机登录Facebook的人仍在增长。Facebook说，今年3月在全球范围内通过手机登录Facebook的用户从去年12月的4.25亿增至4.88亿。
Facebook acknowledged, however, that its mobile growth hasn't led to an increase in ad revenue because it earns almost no money from mobile ads. Last week, the company introduced new ways for advertisers to buy mobile ads.
然而Facebook也承认，移动用户的增长并没有带动广告收入的增长，因为公司从移动广告中几乎赚不到钱。上周，Facebook向广告客户推出了购买移动广告的新方式。
It is still unclear whether Facebook's mobile growth is coming at the expense of personal computer usage, said comScore's Mr. Lipsman. ComScore began tracking mobile use of Facebook only several months ago, so there are no clear trends in the data.
利普斯曼说，目前尚不清楚Facebook移动用户的增长是否是以个人电脑用户的减少为代价的。ComScore几个月前才开始追踪Facebook的移动用户数据，所以数据中还看不到明确的趋势。
Some advertising-agency executives said that Facebook's slowing U.S. user growth rate isn't a concern as long as the company can figure out how to give marketers more opportunities to reach users.
一些广告公司高管说，不必担心Facebook美国用户增长率的放缓，只要该公司能想办法给广告客户提供更多接触用户的机会就行。
"The story line is less about the users themselves,"said Sarah Hofstetter, president of digital ad agency 360i, a unit of Dentsu Inc. "It's more about how they monetize their user base."

日本电通(Dentsu Inc.)旗下子公司、数字广告公司360i的总裁霍夫施泰特(Sarah Hofstetter)说，这件事跟用户本身的关系不大，主要在于如何将Facebook的用户基础货币化。
Others say that not all activity on Facebook takes place directly on facebook.com. For example, websites and apps let Facebook users sign in with their Facebook identity, so users might be interacting with Facebook even when they aren't on the website.
有人说，Facebook上的活动并非都直接发生在其网站facebook.com上。例如，Facebook用户可以用自己的Facebook身份登录其它网站和应用程序，这样即使没有登录Facebook网站，他们可能也在与Facebook进行互动。
"That can understate the real engagement on Facebook," said Brendan Wallace, co-chief executive of San Francisco-based professional networking site Identified, where users can log in with their Facebook user names and passwords.
旧金山职业社交网站Identified的联席首席执行长华莱士(Brendan Wallace)说，这可能会给用户在Facebook的实际停留时间打个折扣。人们可用自己在Facebook的用户名和密码登录Identified网站。
Still, Mr. Wallace said it is important for developers to take note of Facebook's slowing user growth rate.
但华莱士也说，程序开发商应注意到Facebook用户数增速放缓这个现象。
Identified, he said, caters primarily to young users, who are a large part of Facebook's audience. But for products that cater to older audiences, Mr. Wallace said Facebook might turn out to be "just one of many platforms that developers consider integrating with."
他说，Identified主要迎合年轻用户，而这些人是Facebook的主要用户。但他也说，在开发那些迎合年纪较长用户的产品时，Facebook也许只是程序开发商考虑与之整合的众多平台中的一个而已。