I've refrained for a week from asking this question but I'm now giving up. The fried egg means new posts but what is the big red exclamation mark for? I'm a bit embarrassed to ask because I know it's going to be hugely obvious but it's driving me nuts. Thanks!

It's the button to report a bad post (spam etc). The egg shows that a member is on or offline. If you put your mouse over them they say what they are.

I knew I was going to be embarrassed - thanks.