I'm using the theme Twenty Ten, which should display "Posted on (date) by (author)" but my posts only show "Posted on (date)." I can't find a setting to fix this. It's a group blog so I really want the author information to appear. I even tried changing the theme to Twenty Eleven (because it also should show the author info) but it still didn't show up. I feel like I'm missing something very basic here, but I just can't figure it out. Any ideas?
The blog I need help with is robbinslibrary.wordpress.com.