Sitting Shiva is a Jewish mourning ritual for the immediate family of the deceased. Beginning after the burial (which, for Jews, happens as soon as possible after death - preferably the next day), shiva lasts for seven days. The family will gather in the "shiva house", the home of one of them, or preferably the home of the deceased, and receive visitors. You only sit shiva for a parent, sibling, child or spouse.
Shiva is a gentle, compassionate ritual that helps the grieving family cope with their loss. There is no expectation that those sitting shiva should need do anything but be together and receive visitors. Others will help them by cooking and running errands, doing all those little things that would force one to put on a public face during a time of extreme grief.
Sometimes mirrors will be covered by cloth to keep mourners focused on the departed soul rather than on themselves. A candle will be kept lit all week. They will sometimes make a small tear in their clothing or wear a black ribbon, refrain from wearing shoes. Sometimes they will sit on lowered chairs, or even the floor, to symbolize their physical loneliness and depression. Washing is for cleanliness only, not for pleasure or vanity. Marital relations are suspended for the week.
My own family will not be sitting shiva. We're not very devout. As you know, I personally don't even believe in god, so faith is not a factor in my personal mourning.
But there was an aspect of shiva that appealed to me, especially in regards to my presence online. My "home" online would be my facebook page. When I first went there after learning of my brother's death, I felt uncomfortable seeing a photo of myself there, especially one as vain as the one I'd put up just recently. In a symbolic covering of the mirror, I replaced my photo with a black box. At first I had hoped to simply leave my status blank, but Facebook doesn't seem to like that, and had replaced it with "what are you doing right now." So I changed my status to "Patti is home." And then I changed it to "Patti is sitting shiva for her brother," and I'll leave it like that until Tuesday morning, when I'll go back to my usual photo and status updates.
It's also a way for me to let people know what's happened without actually approaching them to tell them directly. I feel awkward about doing that, so my blank photo and shiva status will hopefully get the message across - at least to those who know what shiva is, or take the time to ask.
As little regard as I have for religion for myself, there are some rituals and practices that really have a solid grounding in human compassion and understanding. There's no reason in my mind not to embrace those traditions and let them comfort me in this time of grief.