I don't agree with the view that Thumbs Down or Up don't work.
Poster should be allocated a set number of Thumbs Up and Down for a Calender Year/Set Period and once they use them that's it.
Those that thumb their enemies down or their mates up all the time will soon be identified if a tally is published.
Thumbs up only identify a popular post .................. 90% of the time it's only popular because it suits a particular agenda and not because it brings new and useful information.