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Currently, the expected implementation is to use on a site where you're displaying the same content. For example you write you a blog post "top mountains to climb" on awesomehikingwebsite.com and you also post "top mountains to climb" to your steemit/busy blog. Finally comments then allow you to use the same comments across both blog posts and earn rewards directly from awesomehikingwebsite.com.

The next update will allow users to generate unique IDs so that they can use this comments system regardless of if it should be related to content posted on Steemit.