A boon prot monk used Divine Favor and Divine Boon with protection spells. This combines the damage-reducing properties of protection spells with the healing ability of Divine Favor and Divine Boon. Such a monk was relatively versatile but this versatility came at the cost of maintaining Divine Boon and paying boon's extra energy cost per monk spell cast. Most boon prots used Mantra of Recall or Energy Drain and other Inspiration Magic skills such as Inspired Hex or Drain Enchantment for energy management.
These characters are less popular in both PvP and PvE after the nerfing of their energy management (Offering of Blood had health sacrifice doubled and most of the inspiration line had severely reduced energy gain) and the introduction of strong monk primary elites (Blessed Light, Zealous Benediction, Light of Deliverance etc.)