Very important thing about Google updates such a panda and penguin. The length of the time that visitors stay on your site became more important than ever. Basically if the visitor comes to your site and spend there just two minutes without any other action, Google doesn’t consider your site as much important. It’s the part of the Google updates, which is now necessary for your SEO, and maybe more important than any other SEO stuff.
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Google Update – What’s Important for SEO
What Is SEO / Search Engine Optimization?
SEO stands for “search engine optimization.” It is the process of getting traffic from the “free,” “organic,” “editorial” or “natural” listings on search engines. All major search engines such as Google, Yahoo and Bing have such results, where web pages and other content such as videos or local listings are shown and ranked based on what the search engine considers most relevant to users.