According to Commonplace, their “agree” facility is similar to Facebook’s “like.” But on Facebook, you can also “dislike.” Not so with Commonplace. On Commonplace, there may be an “agree” button, but there’s no “disagree” button. If you disagree with something someone’s said, they expect you to set out your reasons.
It’s interesting to note that with some commonplace consultations, you get hundreds of comments, and very few “agreements,” but with others, you get hundreds of “agreements” and very few comments. No explanation is given for this phenomenon.