What is a search engine?

This heading, "What is a search engine?," now appears for the second time in this book. We first examined the question in Chapter 1, SEO Basics. The reason we have repeated it is that we now need to extend and re-evaluate our notion of what constitutes a search engine.

Do we even need search engines as much as we did before? In 2010, Facebook.com unseated Google as the most visited site on the Web, as measured by total page views as well as time spent on site. Traditional search engines own a decreasing slice of total Internet visitors and page views compared to just a few years ago as social sites come to the forefront and consume greater proportions of user interest. Traditional search engines are still massive, without doubt. The social space is growing rapidly and presence on these alternative properties cannot be ignored. So yes, any business owner or blogger needs to continue to rely on traditional search engines for visitors and customers. However, perhaps...