First, let's look at how crawler-based search engines work (both Google and Yahoo fall in this category).

首先，让我们看看基于爬虫(crawler - based)的搜索引擎是如何工作的(Google和Yahoo都是这种类型)。

youdao

To solve this problem, search engines now rank a site largely based on the number of other sites that link to it.

为了解决这一问题，搜索引擎现在很大程度上根据链接到同一网站的其他站点数来对这个网站进行排名。

youdao

Both search engines have a REST-based interface, which means you feed them a URL with all of your parameters and they give you back XML with the results.

这两个搜索引擎都有一个基于REST的接口，也就是说提供给它们一个URL和所有参数，它们将返回带有结果的XML。

youdao

For video search, AOL has acquired Singingfish.com and Truveo, video-search engines that search based on metadata--like Google and Yahoo!

FORBES: co-founder Sergey Brin

The search for local products and services continues to shift away from the Yellow Pages and online directories and search engines to location-based services via a plethora of mobile apps.

FORBES: A Look At The Boom In Location-Based Services

And in healthcare, hospitals are adjusting emergency room staffing levels based on the frequency and proximity of key words in search engines (e.g. flu symptoms).

FORBES: Why Business Leaders Must Master Data And Analytics