There could be single character posts such as…
Y or N
or 
or 
Choice possibly needs to assess whether a post could just be agreement or disagreement using one or few characters…or require posters to contribute to the thread (namely engage with others)…such as why they agree or disagree. I possibly prefer the latter as it provides explanation to why a particular view or opinion is made.
The other thing is the like button possibly shows agreement from the person clicking on like. This option already exists so does one need an alternative option?
