My Grimoire is for my eyes only as of now. I love my Book of Shadows and I intend to pass it down to my future children when I decide to have them. If and when I decide to create a Coven of my own I may show it to my members but I will most likely keep it to myself and simply teach from it. I think it's better for people to develop their own ideas about spells/rituals rather than copy it from me.
Your Book of Shadows can be as fancy or as simple as you like. It can be anything from a leather bound journal to a simple notebook. The way your Book of Shadows is set up is personal to you. The way you set it up is very important to your Craft. I keep my organized and I hand write everything neatly. I even color in my book because I think it makes it look better than simple black and white (and because I believe magick comes in all colors). Some people choose to do theirs differently such as it being messy and chaotic. Both of these ideas are completely fine. It all depends on you and how you wish to portray your magick.
I keep my Grimoire close to my altar and it is locked when not in use. So what exactly do you write in them? They contain a plethora of magical information along with practical information that the owner deems necessary to write. They can contain secrets, dreams, goals, spells, rituals, basic information regarding the Craft and Wicca, divination, charts, definitions, tools and how to use them, etc. I regard this blog as a type of online Book of Shadows that I don't mind sharing. Other things I reserve for my personal one.
You can put anything and everything in your Grimoire. It is entirely your choice and your right. This is my personal Grimoire.