Lately there has been some discussion on a variety of blogs (Bull Runnings, Crossed Sabers, To the Sound of the Guns, etc) about a better way to categorize some of our blogs. Some of us, and I lump myself in that group, use our blog as a way of compiling information.
Harry uses Bull Runnings to list a ton of 1st Manassas stuff. If I have a 1st Manassas question I often go to his site first as I know it might be there somewhere in the archives.
Don at Crossed Sabers has a ton of info on the Regular Cavalry units in the war. I don't often have a cavalry question but his is a great site the few times I've had questions.
Craig at To the Sound of the Guns uses his blog almost like Brian does with Behind Antietam on the Web. Craig is also a major contributor at Historical Marker Database and uses his blog to give updates on that site as well as talk about his trips to battlefields (a kindred spirit).
Jenny at Draw the Sword offers a daily Gettysburg monument. Her blog inspired me to do something similar with Shiloh monuments here awhile back.
I'm sure there are other blogs like this but these are the ones that spring to mind first. Most other blogs offer up more of a daily thoughts take than systematically examining something. I think I will follow their leads and in the next few days rearrange my blog list with a section for "Information Compilation" blogs.