This is a news feed used for providing users with frequently updated content. Content distributors syndicate a web feed, thereby allowing users to subscribe to it in an RSS reader or via email.
People are not regularly coming to your blog to see if you have any new blog posts. Some might, but the majority won't. That's why you want to use feeds: so your readers can get their blog posts via email, or via an RSS (really simple syndication) feed, so they never have to remember to come back. Your content simply comes to them.
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