"like" on facebook

Facebook allows you to comment on posts, as you know. And, for the extra-lazy who still want to be heard, you can just click "like" to show your approval.

Oddly enough, though, if you follow something like an NPR newsfeed, you get something along the lines of "Wildfires Kill Thousands" with a link to the story.

What exactly are you saying when you click "like"?