media checkin

 Media check-in  is a somewhat controversial concept that refers to a type of virtual check-in post, where the "location" is an item of consumable media such as a book, audio, video, or realtime media such as a radio or TV broadcast.

Dilutes the meaning of checkin
checkins referred specifically to explicitly notifying your friends (sometimes followers) that you were at a physical location, typically a venue, as pioneered by Dodgeball and then Foursquare (and copied by Brightkite, Gowalla, Yelp, Facebook, and maybe others like Loopt).

The notion of a "media check-in" is completely artificial, has always felt like a forced concept / someting marketingy/brand-y/virtual to distract people from actual physical checkins. As such the use of the term "checkin" as referring to something virtual dilutes the meaning of the term.

Just a bookmark
Whether "checking into" a book, a page in a book, a movie, they are actually all just "bookmarks", especially in the example of "reading progress" mentioned above - which is a literal use of physical bookmarks.

There is no need for a different post type to express this concept.

gRegor Morrill

 * is experimenting with posting reading progress check-ins as of 2015-01-25.
 * Currently using  and   to indicate progress. The percentage complete can be calculated and graphed from these values.
 * Using  and   for the book title. The identifier's href is in the format.
 * Manually POSSE to Goodreads.
 * Feedback is welcome, since this may not be the "best" way.

Tom Morris

 * tommorris.org: book checkin prototype

Goodreads

 * Goodreads allows you to check-in your reading progress.

Dead services

 * GetGlue (later renamed tvtag) allowed you to check in to TV, films, music and other media. Example stream

Open data sources

 * OpenLibrary
 * MusicBrainz
 * Wikipedia via dbpedia with SPARQL