Facebook Like Button (2009)
The Like button launched; engagement became a ranking input.
DateFeb 9, 2009
PlatformFacebook
TypeFeature
Who it affectsAll pages
What happened
Facebook launched the Like button in February 2009. Likes became a simple, widespread signal of interest and, later, an input into feed ranking and ad targeting.
Who it affected
All pages.
What it means for marketers today
Likes are still a signal, but comments, shares and watch time usually tell Facebook more about how valuable a post is.
Related
See the full Facebook Algorithm & Feature History (2006–2025)