For the most part, it's just me. Sometimes my trainer will ask me what I've been eating, particularly if I've been off-plan for a few days, and that has sometimes been very helpful. Also, knowing that my SO will probably notice if I eat every last piece of food in the house is sometimes the only thing that stands between me and the fridge.
As a general rule, though, I agree with JayEll that I don't want my friends and family that involved in my weight situation. Particularly with my SO, I think it is very important that I be responsible for what I eat and when I exercise, and that he remain supportive but completely neutral on these issues. 1) We have enough stuff to fight about without adding my diet and exercise to the list and 2) It is important that I feel like he loves me the way that I am; that he isn't trying to make me skinnier or prettier. It's great when he compliments me, but I don't want him telling me that I shouldn't eat something or that I've put on a few pounds. That's my responsibility.
And my friends just don't want to hear the day-in day-out stuff. We talk about what I'm doing sometimes, but some of them are struggling with their own choices about their own food and exercise, so they don't want to hear a constant recitation of how many calories I'm eating or how much I've exercised. And while that stuff is endlessly fascinating to me; not so much for others.
So really, it is 3FC where I pour out my heart about my diet and exercise. And I sometimes use the planning threads on 3FC to hold myself accountable. Honestly, this forum has been a huge source of support!