For example, the top 50 websites in the us on average installed 64 pieces of tracking technology onto the computers of visitors, usually with no warning.

例如，全美最大的50家网站平均在访问者的电脑上安装了64种追踪技术，而且通常都没有任何警告。

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We can put tracking tools on the attackers' computers so we know who they are, where they are coming from, where they are going and when they are doing it.

我们可以在攻击者的电脑上安装追踪软件，以此了解他们是谁、从哪里来、去哪里、什么时候会展开攻击。

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Tracking companies can use this data to uniquely identify computers, cellphones and other devices, and then build profiles of the people who use them.

在线追踪公司可根据这些数据为每台电脑、手机或其它电子设备建立唯一的数字身份，并以此建立使用者的档案。

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It has deals with companies such as Dell and HP to embed its tracking agent into their computers' boot-up software, where it is more difficult for a thief to remove than from the hard drive.

FORBES: Magazine Article

Despite these promises, the FTC charged that Google placed advertising tracking cookies on consumers' computers, in many cases by circumventing the Safari browser's default cookie-blocking setting.

ENGADGET: Google to pay $22.5 million to settle FTC charges over tracking cookies in Apple's Safari browser

In that instance, Google used special computer code to install tracking files known as cookies on some people's computers even if the device was set to block such tracking.

WSJ: Google Engineer Told Others of Data Scoop