Facebook like button

The internet social networking site Facebook introduced its “like button”  feature for the first time. Clicking the button with a thumb up icon indicates a user's positive reaction to the content of the web page on which the button is located. In 2011, Google introduced a similar button to mark one’s favorite content called the +1 button for its Google+ social network.

2009/02/09

https://www.livescience.com/20727-internet-history.html