Sometimes they are collected into a posts-elsewhere section in a footer or sidebar of the post.
Here are some use cases that help illustrate why.
Shortcut for web actions
Syndication links are a good short term substitute for actual web action buttons.
Linking to a syndicated copy (e.g. to a Twitter copy) can provide a quick way for the user to reply (or use other verbs) on the copy of your post (e.g. tweet copy) on that site. This may be easier than (and hence a shortcut for) providing web-actions on your post itself.
This is a good short term use-case until you implement "reply" (and other common verbs') webactions/buttons on your posts.
- "View on Twitter" - is neutral enough and provides a simple path for Twitter users to fave/reply/RT. See posts elsewhere examples for more examples.
Links to syndicated copies can also be used as part of the fallback for people who don't use webactions yet, e.g. a Twitter reply intent URL API link as fallback for a reply webaction.
On reply posts, it may be particularly helpful to provide links to syndicated copies in order to view the fully threaded conversation on those silos (unless you've implemented this yourself on your own site).
- E.g.: View this conversation on Twitter - more compelling than "View this post on Twitter".
This is also a shortcut to implementing reply-context presentation, e.g. with a link like:
- "View Conversation on Twitter" - provides a reasonably obvious way to discover what conversation a reply is part of, including the original that it is in-reply-to. See posts elsewhere examples for more examples.
Enable original post discovery
- Enable those who implement original-post-discovery to post replies linking directly to my post permalinks as well as (instead of only) POSSE their reply threaded to the respective POSSE tweet. e.g. this reply from Barnaby should be in-reply-to my original post instead of the tweet copy. Adding the rel-syndication link enables step 3 of the original post discovery algorithm: "see if it [the post permalink] links back to the POSSE'd copy with rel=syndication". Having those who reply to indieweb posts link directly to them (rather than to tweet copies) is better indieweb behavior (enabling/encouraging peer-to-peer indie to indie links rather than indie to silo links), providing a more indieweb user experience.
- Aaronpk: "would at least let me auto-discover your syndicated posts when replying"
Enable POSSE CRUD
Technically you only need to store syndication links for this but having actual syndication links in your UI better ensures that they're accurate and work.
The presence of syndication links in your publishing system provide key information for implementing the Read, Update, and Delete portions of POSSE CRUD.
Possible presentation / link text for links to syndicated copies, e.g.:
- Tweet permalinks (POSSE copies on Twitter)
- (Twitter icon) "View on Twitter" for notes posts
- (Twitter icon) "View conversation on Twitter" for reply posts