“I saw what you wrote, and I want to acknowledge that you wrote it, but I have nothing clever or important to add.”
“I disagree with you, but this is obviously important to you and I’m impressed by your enthusiasm.”
“This is wonderful! I love it so much! It is hilarious, sweet, inspiring, and/or I am so happy for you!”
“You have posted a link to something I should probably watch or read to improve my mind, but I am reading this on my phone and I’m close to my data limit. There is no way I will ever remember to come back to this later, but thank you for trying.”
“My finger slipped.”
“You liked something of mine and I want to return the favor.”
“I don’t really get the joke, but a lot of other people liked it, and I don’t want to be left out.”
“You don’t post often enough, and I want to encourage you to write more.”
“I like this.”
… or some combination thereof. They really should add more buttons.
(I don’t mean my “Like” as being smart-assy. I actually like this, ie. “This is wonderful! I love it so much! It is hilarious, sweet, inspiring, and/or I am so happy for you!”)
(I would like to use the word “smart-assy” more often. Not necessarily to you. It’s more of a global desire.)