网络股为什么再次走红

    2013年注定是一个股市重新爱上互联网的年份。问题在于，这次再续前缘到底会是天长地久的一段姻缘，还只是另一次昙花一现的迷醉。

    自从2000年互联网泡沫崩溃后，只有极少数互联网公司被市场捧为科技巨星：eBay和雅虎（Yahoo）红极一时的日子已经是十年前了，随后渐渐风光不再。谷歌（Google）2004年上市，此后业绩一直稳步增长，但很少有上市的互联网公司能获得类似的成功。

    几年前，一批新一代初创公司开始涌现。它们主要围绕社交网络、本地电商和移动应用这些新技术和新功能而创建。很快，其中的佼佼者就纷纷上市，而另外一些，如社交游戏公司Zynga和OpenTable等公司的股价不断起起落落。只有包括商务社交网站LinkedIn在内的少数公司才获得了投资者持久的追捧。

    今年的情况则有所不同，几乎所有依托于互联网商业模式的上市公司都发现，自己的股价正如创始人刚刚上市时梦寐以求的那样在猛涨。其中最著名的当数Facebook。还记得它的股价一度跌到了18美元，还不到发行价的一半吗？而那仅仅是一年前发生的事。

    最近互联网股价这股热潮的最大推手正是Facebook。在它刚刚上市的头一年里，由于市场普遍担心它无法通过手机广告赚钱，因此它的股价始终在低位徘徊。不过，这家公司最近的财报显示其财务状况正在改善。此后，Facebook的股价翻了一番，也推动了其他能从移动互联网中赚钱的公司股价开始上涨。

    Facebook效应对网络股的重大影响是显而易见的，大量这类股票在2013年都开始上涨。LinkedIn上涨了112%，流媒体音乐服务公司Pandora涨了199%, 房地产估值网站Zillow涨了204%，点评网站Yelp的涨幅更是高达 285%。就算是那些被视为网络股中麻烦缠身、业绩欠佳的公司也跟着水涨船高：Zynga今年涨了60%，团购网站Groupon涨了135%（不过并非所有近期上市的网络股都有这么红火的走势，比如Demand Media就下跌了32%）。

    市场对网络股的这种大手笔投入促使更多科技公司申请上市，其中有一些已获得热烈追捧。广告科技公司Rocket Fuel九月末上市首日股价就近乎翻倍，此后更是节节攀高。而Twitter公司周四提交了外界期待已久的IPO申请，一旦上市，它的市值有望达到100亿美元，而它迄今为止还未能实现盈利。

    如果Twitter以如此高的市值上市后股价还能上涨，无疑会对网络股的集体飘红再添一把火。而对那些亲历过网络泡沫大起大落的人来说，不免会产生这样的疑问：这种狂飙突进何时会面临失控？对理智的投资者来说，这些热门股票什么时候会变成烫手的山芋？  

    2013 is proving to be the year that the stock market fell back in love with the Internet. The question is whether the love affair this time will be an enduring one or just another bout of exuberant infatuation.

    For years after the dot-com crash of 2000, only a handful of companies at a time were received as tech stars: eBay (EBAY) and Yahoo (YHOO) were hot a decade ago, then lost their mojo. Google (GOOG) went public in 2004 and has enjoyed mostly steady gains since, but few web IPOs that followed saw similar success.

    Several years ago, a new generation of startups emerged. They were built around new technologies and features like social networking, local e-commerce and mobile apps. In time, the best of these companies listed their stocks on the public markets, and some, like Zynga (ZNGA) and OpenTable (OPEN), saw their prices rise and then fall. Fewer, like LinkedIn (LNKD) won a more durable favor among investors.

    This year, nearly all public companies relying on web-centric business models are seeing the kinds of rallies that founders dream of when going public. The most notable example is Facebook (FB). Remember when the stock was trading at $18 a share, less than half its offering price? That was only a year ago.

    Facebook, more than any other company, is responsible for the recent surge in web stocks. Its share price languished for much of its first year in the market amid concerns that it hadn't found a way to monetize mobile advertising. The company's most recent financial report, however, showed that was changing. Since then, Facebook has seen its stock price double, spurring rallies in other companies able to draw revenue from the mobile web.

    As important as the Facebook effect has been on web stocks, many of them had been rising throughout 2013. LinkedIn has risen 112%, Pandora (P) 199%, Zillow (Z) 204%, and Yelp (YELP) 285%. Even companies seen as troubled laggards in the sector are benefiting: Zynga is up 60% this year, and Groupon (GRPN) has gained 135%. (Not all recent web IPOs are thriving, however: Demand Media (DMD) is down 32%.)

    This spirit of generosity toward web stocks is prompting more tech companies to file into the IPO queue, and some of these are receiving warm welcomes. Rocket Fuel (FUEL), an ad-tech company, nearly doubled on its first day of trading in late September and has risen even higher since then. And Twitter, which filed Thursday for its long-awaited IPO, is expected to be valued at $10 billion when it goes public, and it has yet to show a profit.

    If Twitter's stock rises after listing with such a rich valuation, it could add even more fuel to the rally in web stocks. And that would raise questions familiar to anyone who rode the boom-and-bust roller coaster during the dot-com years: When is a rally getting out of hand? When does a hot stock become too hot for sane investors to touch?