the blue pin means that it's a Sticky thread, regardless of how the other threads move up and down accourding to replies, threads that are stickies remain at the top.
I'm going to have to remove the trash bin. It just means that there are deleted posts within the thread, but you won't see that.
I don't think too many people use that button, although they can. If a post has spam, bad words, wrong message, etc. you can click that button and send in a complaint. This goes to the Moderators and Admin and someone should look into that post concerned.