People can often share misleading, irrelevant articles
People on social media platforms share articles either after reading through and defining the context of the article or just by following what the headline says.
The individuals in the latter group can often fall for incorrect stories and share information that is factually wrong or no longer relevant with their friends, family. This might then mislead the others too.
In the post announcing the feature, Facebook's Feed and Stories VP John Hegeman clearly notes that the prompt will just tell the user how old the article is rather than blocking them from sharing it completely.
If you feel that despite being old something is worth sharing, there will be a 'Continue' button on the prompt. Otherwise, there will be a 'Go back' option.
Timeliness is an important piece of context, Hegeman added
"Timeliness of an article is an important piece of context that helps people decide what to read, trust, and share. News publishers, in particular, have expressed concerns about older stories being shared on social media as current news, which can misconstrue state of current events."
Along with this, Facebook is also working on the other share alerts, including one that would automatically show source links for COVID-19-related articles and suggest the user to visit the social network's own COVID-19 Information Center for authoritative health information.
To note, the company already displays a context button on its feed that provides information about the source of articles when clicked manually.
The feature from Facebook, which is rolling out globally starting today, comes just a few weeks after Twitter introduced the feature to nudge users into reading an article before actually sharing it to their followers.