why the hell would you want to add a "foe"????
Well let's suppose just for the sake of discussion that I get fixated on someone like say Salty. I follow him around on all his posts and not just disagree but insult him as well. I call him a liar and worse. Maybe he does not want to get drawn in to my pettiness but as I continue to insult him he is tempted to retaliate. Maybe he just finds my posts offensive and does not wish to read them. Instead of having to fight the urge to retaliate and ignore me he can just list me as a foe and he will not even see my posts. Basically it is the same as what has commonly been referred to on other bulleting boards as the /ignore feature.
All message boards have such a feature. I have had to use this feature twice on these boards because I picked up a stalker. A drastic measure but effective. He or she may still be insulting me but I never see it and thus are not tempted to respond with a childish discussion that nobody else wants to read. Win for me and win for the community.