Everything Under the Moon

Okay, so I'm relatively new to the usage of forums, and I've noticed what I think is called a topic icon.
Sometimes they are just circles with lines in them. Sometimes they are moving. Sometimes red and moving.

I would like to know what these mean, and what ones there are.
Please and thank you.
I hope this is posted in an OK place

Also, what the different colours of the usernames each mean?

I believe blue means a topic where you've read all the posts; red indicates it's unread or has some posts you haven't read. Moving threads indicates particularly active topics. Lightbulb icons indicates "stickies" -- threads that are particularly relevant that moderators have put at the top of the forum for greater visibility.

Gray usernames indicate new users; they turn to a magenta-purple for regular members. Blue are mods; black are admin.