[mothered]

Sometimes I find myself liking posts just because they aren't at the point where a reply is needed, but I would like the other user to know that I acknowledge their post.

This ^^^

I too, often use the Like functionality when a reply Is not really warranted and simply want the given member to know that I've acknowledged their post. Generally speaking, "Like" Is something that you can relate, conform or agree to, whilst "Acknowledge" Is a form of recognition.
EDIT: Typo.