SEO and Google have been synonymous - while most SEO tactics and approaches are search engine agnostic, they often get tied to Google ranking. It's fairly obvious why this is the case - Google is the most popular search engine with 67.3 percent of market share according to comScore.
Google also addresses (and condemns) SEO efforts more frequently than toner engines. But SEO isn't just for Google, and really isn't just for search engines, either. Every social media network has some type of search functionality.
As social media usage has risen, so has the volume of searches on these networks (YouTube is the second largest search engine behind Google and Twitter receives 2.1 billion queries per day).
To understand what is popular, relevant, and credible, the search engines are turning to social media.
Via Antonino Militello