I think I know what I'm doing

Thank you to all of you who tried to help me with my blogger problem, I did as Mildred said and unchecked the stay signed in box and then it allowed me to leave a comment but, I still don't understand why these profile things have suddenly started appearing, am I being thick?

Problems

Can anyone tell me why I cannot leave comments on some of the blogs? I write out my comment and then when I try to leave the comment I am asked for a profile and then when I sign in nothing happens. Can anyone help?