That's not the semantics of the Like button however. The Like button's semantics, as used by most people, are "I have read your post, don't have anything meaningful to add, and agree with you and/or express my post-appropriate social action but do not feel affected enough or close enough to you on the social graph to leave a comment."

The meaning of a Like is extremely contextual. And most people know this.

Granted, a lot of newbie users get confused.