What Are Google?

What are Google, Bing, or other search engine operators for locating specific file-types, for example, .PDF?

Imagine that you have just landed in Rome’s Fiumicino Airport. You have six hours to explore the city. But you don't know anything about the city in advance, you don’t have a map or a guidebook, and you have to walk in order to get from place to place. People might tell you how to get to nice places, if you ask them. You will probably see some lovely sights. But you are likely to miss many historical places and touristic attractions, because you are using a slow method of exploration, to tour among hundreds of thousands of buildings. Next, after this crude analogy, consider the internet. According to How Many Pages It Takes to Print the Entire Internet, on 2015 there were 4.54 billion pages on the web (probably many more today). You can still go through the pages one by one, and might find some interesting and useful pages. Now, if you use a search engine, you will get closer to what you look for much more quickly. So the first benefit from using a search engine is Effectiveness. The next issue is authority. How do you know whether a random page is a good source of information for a given subject? Search engines try to place the most authoritative pages first. The PageRank algorithm was one of Google’s differentiators on their way up, by giving authoritative results precedence. Next - is the information up to date? Google and other companies are hard at work to give relevant, authoritative and timely results. Location-based search also comes to mind - If I’m searching for a restaurant in Jerusalem, I expect to get suitable results for my town, rather than for, say, San Francisco. The list can go on. IMO, search engines give us access to a much more useful part of the internet than browsing using URLs. After you have accumulated a large enough set of pages that interest you on a constant basis, you can of course use bookmarks.