The effect is similar to the use of external images to track E-mail.

由此带来的影响类似于使用外部映像跟踪电子邮件。

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With a little bit of work, we could see this being a useful tool for businesses that are trying to track e-mail campaigns, product inquiries or support requests.

再稍微雕琢一下的话，它就能成为一个很好的商务工具，能够试着追踪电子邮件活动、产品查询或者技术支持需求。

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Harry Joiner, an e-commerce recruiter who focuses on mid - and senior-level executives, is on track to handle nearly 130 executive searches this year, up from about 70 in 2009.

哈里·乔伊纳，电子商务主要针对中级和高级管理人员的招聘专员，今年以来已经跟踪处理近130个管理职位的猎头，2009年仅仅有70个。

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He says unlike e-mail, the short wave transmissions are almost impossible to track.

VOA: standard.2009.06.06

By posting e-mail addresses on public sites as targets for each others' phishing e-mails, gangs of scammers are able to track each others' newest tricks and keep up with the latest innovations.

FORBES: Future Phishing

In those days, mail-order firms (there was no E-commerce) argued it would be too complicated to keep track of the different sales tax rules and rates around the country.

FORBES: Time For Congress To Step Into Battle Over Internet Sales Taxes

Google Now identifies these types of e-mails and turns them into cards, so you can track a package you're waiting for or use your phone as a boarding pass at the airport.

CNN: Google's predictive search comes to iPhone, iPad