The concept has been discussed many times in the past. And the consensus is that long-term members didn't like the idea of turning conversations into a popularity contest.
That said, there is a literal popularity contest on this forum - the Foolmewunz Memorial Language Awards, the thread for which you will find in Community. The Nominate button at the bottom left of a post allows you to nominate that post for an award, which is decided monthly and the winner of which gets a nifty banner beneath their name. It's not the same as a Like button, though - it should be used to express appreciation of the language of a post, not to simply express agreement with it.
This is one of just many ongoing traditions that await your discovery. Soon, you too will discover the joy of dicksing your own potatoes!