Can I skip someone in the post order?

So much has changed since I lasted played RPGs ten years ago. I have a few questions. The first, I understand that new etiquette says that when Bill, Bob, Pam, and Sue are playing in a thread (originally posting in that order), that it should be continued. However, I was wondering what the etiquette was if Bob's character happens to ask Sue's a question? Does Pam have to post before Sue can?

Also, I've come across a few terms I'm not at all able to find the definitions to. They are Threadlog, Pawprints, (not used here but thought I'd ask) Storybooks. Could someone please define at least the first two for me please?

Also, while I'm at it, I was mildly concerned about graphics. In popular animal sim games I play, it is law that all photos, brushes, and related material be properly credited and copyright free. I haven't seen that evidenced here, so I must ask, what are Wolf's regulations on graphics, copyright, and crediting?