Can anyone help me out to understand a feature of Google analytics named "Trackback" and what is it importance?
If you write a post and reference content elsewhere, that’s providing a Trackback to the article. The reason bloggers like Trackbacks is that it offers validation that your content is seen as informative enough that someone else wants to share with their readers too. The benefits of this is that you get extra insight into your traffic, seeing what content attracts links and tracking conversations that link to your content. This feature is part of Google's social analytics and plays a part in determining what Google calls social impact. The company has said that four elements define a site's social impact: Sources, conversations, pages and social plugins. Sources looks at how people get to your site, conversions focuses on the monitory value of social traffic and how it impacts your business, pages highlights what pages and content are shared, where they're being shared, and how, and social plugins shows you which content is being shared and which sites they're being shared on. Analytics pieces these factors together and displays a summary of social impact on its overview report through its social value graph, which compares the number and monetary value of all goal completions (if you've set them) versus those that resulted from social referrals.