A site author may choose to publish a list of sites that have "reposted" their content, similar to how Twitter shows the people who have "Retweeted" a given Tweet.

The proposed u-repost property would be used to indicate that the linked resource is a repost of a page.

This property would be used in a site's comment section to distinguish a repost semantically.

u-repost should not be confused with u-repost-of. u-repost-of is used by a site to say they are creating a repost of the linked resource. u-repost says that the linked resource is a repost of the page where the attribute appears.