The help text is crucial to make this field understandable. It gets displayed below the form input on the admin, so maybe we should be asking the question this answers: "How often should this snippet be shown to users?"

Also, this should probably have a `verbose_name` that isn't weight. While the weight metaphor makes sense to us as developers, the admins probably won't get the comparison as intuitively as we do. Maybe "Prevalence"?