this is something i was curious about, after having found AP-based services for other needs (e.g. calendars, books, etc).
i was originally hoping for AP-enhanced place reviews, but tracking/timeline is an added bonus layer. count me as interested.
the only couple things related i found are:
- https://github.com/social-web-foundation/places.pub
- https://www.reddit.com/r/programming/comments/1b9t7qn/rebuilding_foursquare_for_activitypub_using/