卡玛克什•西瓦拉马克莱斯娜从没想过进入广告行业，更别说经营一家创业公司了。但这位37岁的斯坦福大学信息理论博士毕业生在见到AdMob创始人奥马尔•哈姆伊后，毅然离开华尔街，在2007年加入了AdMob。在那里，她创造了很多具有深远影响力的算法来改善产品表现，比如使广告对用户更具有针对性。

    “当时是功能手机的时代。”西瓦拉马克莱斯娜回忆说。iPhone发布那年，她拥有的仍然是老派手机，不仅屏幕小，而且网络浏览器只具备最基本的功能。“那时，谁会用手机上网呢？我们只是用它们来打电话。它们是语音通信设备，而不是数据通信设备。”

    两年后，长期占据互联网广告霸主地位的谷歌（Google）以7.5亿美元收购了AdMob，这是谷歌最大的收购之一。西瓦拉马克莱斯娜在谷歌呆了短短6个月后，就离开公司自创门户，去完成AdMob开创的事业。

    “如果说AdMob的一个未竟遗愿需要去完成，那就是下一代移动广告。”她解释说。如今，这家位于圣马蒂奥的创业公司拥有36名员工，从凯鹏华盈（Kleiner Perkins）和红杉资本（Sequoia Capital）等公司手中获得了2,050万美元投资。该公司声称，现在规模为72.9亿美元的美国移动广告行业错漏百出。很多营销人员继续把移动和桌面行为当作互不相关的数据集，这是错误的做法，因为现在很多消费者都拥有多台设备。例如，他们不仅用台式机上网，还用平板电脑或智能手机上网。

    去年秋天，Drawbridge推出了对消费者行为有更深入了解的广告产品。例如，有个智能手机用户搜索平板电视，看到了百思买（Best Buy）的销售广告。于是他点击广告，却发现自己宁可用台式机登陆百思买网站来浏览和购买该产品，也不愿在屏幕相对较小的手机上进行浏览。“百思买不知道，点击其移动应用的那个人与用台式机登陆其网站的那个人是不是同一个人。谷歌也不知道。”曾为谷歌效力、现在担任Drawbridge产品副总裁的埃里克•罗森布鲁姆解释说，“百思买只知道自己因为某人点击了其广告而向谷歌付费，但此人并没有购买电视。随后，另外一个人登陆百思买网站并购买了一台电视。”

    属于同一个人的各种设备通常会经由数字交换机或市场发出类似的广告需求。Drawbridge能够坐在这种数字交换机的旁边，观察到这些需求。几周后，Drawbridge的技术可以识别某用户在不同设备上的行为模式，并把它们匹配起来，准确率达到70%以上。在百思买和谷歌的例子中，Drawbridge的价值显而易见：百思买能够知道其广告是否直接促成了购买，而谷歌或许可以向那个广告收取更高费用。

    Kamakshi Sivaramakrishnan never planned to go into advertising, much less run a startup. But when the 37-year-old Stanford graduate, with a Ph.D. in Information Theory, met AdMob founder Omar Hamoui, she turned her back on Wall Street and joined AdMob as a research scientist in 2007. There, she developed large, sweeping strings of math to help improve things like making ads more relevant to users.

    "It was the era of feature phones," Sivarakmakrishnan remembers. Though the iPhone launched that year, Sivaramakrishnan still owned an old-school cell with a small screen and skeleton web browser. "Who browsed the Internet on their phones then? We just used them to talk. It was a voice communication device -- not a data communication device."

    Two years later, Google (GOOG), itself the long-reigning Internet ad king, scooped up AdMobfor $750 million, one of the largest acquisitions the company ever made. Sivrakmakrishnan stayed with Google for a brief six-month stint before striking out on her own to finish what AdMob started.

    "If there is an unfinished legacy of AdMob that needs to be solved, it's mobile advertising in this next generation," she explains. Now the 36-strong San Mateo-based startup, with $20.5 million in funding from backers like Kleiner Perkins and Sequoia Capital, argues that today's $7.29 billion U.S. mobile ad industry is broken. Many marketers continue to treat mobile and desktop behavior as separate sets of data, a flawed philosophy given how many consumers own multiple devices now. They may start surfing the web on the desktop, for instance, but continue doing so on their tablet or smartphone.

    Last fall, Drawbridge debuted ad products that know better. Say a smartphone user searches for flat screen TVs, and they see a Best Buy (BBY) sales ad. They click on it, but realize they'd rather browse and buy on BestBuy.com from their desktop instead of scrolling on their phone's comparatively smaller screen. "Best Buy doesn't know that was the same person who clicked on their mobile app, and Google doesn't either," explains Eric Rosenblum, another Google alum and Drawbridge's VP of product. All Best Buy knows is that it paid Google for an ad someone clicked on, but they did not buy a television, and that later, a different person came to BestBuy.com and bought a TV."

    Devices that all belong to the same person normally send off similar ad requests or requests made through the device by way of a digital exchange or marketplace. Drawbridge is able to sit on the sidelines of this digital exchange and observe these requests. Over several weeks, Drawbridge's tech recognizes a user's behavioral patterns across different devices and with 70%-plus accuracy, matches them up. In the case of Best Buy and Google, the value of Drawbridge is obvious: BestBuy (BBY) would know its ad directly contributed to a purchase, and Google could potentially charge more for that ad.

    到目前为止，Drawbridge已经配对了4.71亿部设备，产生了数亿个桌面和移动用户档案。旅游预订服务网站Expedia已经在尝试Drawbridge的广告解决方案。这家创业公司的下一步是什么？更深入地挖掘用户数据，告诉营销人员各种信息，比如某人重复登录某网站的频率，以及他们在登录后，是从移动端还是从桌面端进行浏览或点击。西瓦拉马克莱斯娜估计，他们目前的广告解决方案能够使广告活动的效果提高3倍。

    考虑到创始人的敬业精神，Drawbridge的员工们应该很快就能实现这个目标。在公司成立之初，异常勤奋的西瓦拉马克莱斯娜鼓励员工周末加班，她甚至想过是否在圣诞节时让员工放假。西瓦拉马克莱斯娜在其破旧的1990年款丰田科罗拉因为事故而彻底报废后，才最终换了辆新车。“她太忙了，没时间去买车。”凯鹏华盈合伙人和Drawbridge投资人马特•墨菲笑着说。墨菲曾提出帮她买一辆（但他最后没有这么做）。

    对于墨菲来说，这只是让西瓦拉马克莱斯娜可以继续工作而付出的小小代价。墨菲解释说：“她正在解决一个大问题。坦白地讲，这个问题对其他人来说极其困难。”（财富中文网）

    译者：千牛絮

    The startup has paired over 471 million devices so far, yielding complete desktop and mobile user profiles that number in the hundreds of millions. Travel booking site Expedia (EXPE) is already testing Drawbridge's ad solutions. Drawbridge's next step? Drilling deeper into user data and being able to tell marketers things like how often someone comes back to a web site and once they return, whether they're viewing or clicking from mobile or desktop. Already, Sivaramakrishnan estimates their current ad solutions can offer marketing campaigns as much as 300% in boost.

    Given its founder's dedication, the Drawbridge crew should get there quickly. When she first started, the committed Sivaramakrishnan encouraged people to come into the office on weekends and even wondered whether it was OK to give employees Christmas Day off. Indeed, it was only after her beat-up 1990 Toyota Corolla got totaled in an accident did Sivaramakrishnan finally get a new car. "She was so busy she couldn't buy one," chuckles Matt Murphy, a Kleiner Perkins partner and Drawbridge investor, who offered to purchase one for her. (He ultimately didn't.)

    To Murphy however, that would have been a small price to pay so Sivaramakrishnan could continue her work. Explains Murphy: "She's going after a big problem that frankly, is going to be extraordinarily hard for others replicate."