Very sad news. It came as quite a surprise too, as I knew of her diagnosis late last year, but not that her condition had deteriorated so quickly over the last several months when I hadn't been around here much. She still seemed to be soldiering on when I was on more often before the birth of latest daughter, at which time she was still posting fairly regularly. It really doesn't seem that long ago. I had noticed her recent absence and seen a few posts referring to an un-named person or people being in need of support, etc, and wondered if they could possibly be about her, but nothing definite... Mark's post has explained the unhappy situation pretty clearly now though.
Unlike some members I didn't know her IRL or off the forum, and I never saw her talk a great deal about herself here either, but I could see that she put a lot of time and effort into this forum: on the one hand she always seemed to be striving to be a fair and impartial moderator who tried to calm down fraught situations and defuse quarrels without taking sides; while on the other she was ever-present with thoughtful advice and information about birds, a warm welcome to newcomers, and personal support to whoever seemed in need of it. Her absence will be felt by all the regular members here for as long as the forum continues, I'm sure.
My condolences to Mark, and I hope those who know him personally are able to give him whatever support he needs. It's all too easy to overlook how difficult it is for the bereaved one who is still with us in situations like this; they not only have a lot of weight on their shoulders, but are having to bear it alone for the first time in many years.