comment reactions

 comment reactions  are a feature of several silos that allow users to tap a hollow heart or other affordance next to comments on posts to like a specific comment or sometimes react with a limited set of reacji.

Facebook
Facebook was perhaps the first to provide the ability for people to like (👍🏻) comments displayed on posts, eventually expanding to allow a specific set of reacji.

GitHub
GitHub has allowed users to react to comments on issues and pull requests for quite some time with a limited set of reacji that they expanded a bit over time.

Instagram
Instagram implemented the ability to like (❤️) comments on posts sometime after ~2019.

Strava
Strava experimented a bit with various icons and settled on an initially empty heart (♡) similar to Instagram as an affordance which turns into a deep red orange heart (🧡) the same color as the Strava logo, since 2022-07. Unlike other silos, once "liked" you cannot unlike a comment.
 * 2022-07-28 New! Activity Comment Reactions