Add a reaction
Open the article you want to react to.
Tap the reaction button in the bottom action bar.
A quick-reaction bar appears with 5 standard emojis. Tap one to react instantly.
Want something different? Tap + in the quick-reaction bar to open your device's full emoji keyboard and pick any emoji.
Your reaction appears on the article right away. The article shows the top 3 most-used reactions along with the total count.
Note: You can only have one active reaction on an article at a time. Picking a new emoji replaces your previous one. Tap your active reaction again to remove it.
See the full breakdown
Tap the reaction row on the article (the top 3 emojis and the count) to open a panel showing every reaction and how many people used each one. You can add or change your reaction from this same panel.
Important: If an admin turns off comments for an article, reactions turn off too since they use the same permission setting.
FAQ
Why can't I react to an article?
The admin has likely disabled comments for that article, which also disables reactions.