Search engines view on Guest blogging is not as bad as article marketing, since article marketing strategy has gone down due to "content spinning issue". A guest blog post cannot be duplicated as it is highly moderated by the owner of the blog site and if a blog site provides useful information that helps search engines produce educated blog post, they will not accept guest bloggers that they believe would damage of the reputation of their blog.

The main important purpose of guest blogging is to contribute to the blog site about something related, useful and informative insights on the topic of the blog to share more knowledge to the target audience of the blog site. Google, respects blog sites with useful information that can help them provide related and educational results on every search queries. 

Guest blog post may be considered as white hat seo technique if the information said in the content is not copied from another blog post, article post or website content. If it has something good to contribute to the public and if it helps search engines provide original content that may benefit both, search engines and internet users.

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Google view's on Guest Blogging