Facebook introduced the Like button in 2009.
The feature was first enabled on February 9, 2009, giving users a quick way to signal approval or enjoyment without writing a comment. Initially, people could use it on status updates and other shared content, including photos, videos, links, and advertisements. A Like also displayed a count of users who had selected it and could influence what appeared in friends' News Feeds.
The Like button later expanded beyond Facebook itself. In April 2010, Facebook launched social plug-ins that let external websites add a Facebook Like button, linking their pages to Facebook's social graph. The button was extended to comments in June 2010.
A common mix-up is confusing the original 2009 Facebook feature with the external website plug-in, which launched in 2010. Facebook eventually added Reactions worldwide in February 2016, but those supplemented rather than replaced the Like button.