What do these Icons mean?

Next to every post is a blue or orange icon. Some are pulsating and others have a little red dot at 2 O'clock. I can't find anything on the site to explain this.

 

If it's orange it means the thread has had a new post since you last read it. Blue means there's nothing new and the red dot appears next to threads you've posted in.

 

What do the pulsating ones mean?

 

that they are active, lots of people looking.

 

It means that 15 or more people have posted on that thread.

 

The red dot means you have contributed to that thread.

 

Bex mentioned that I'm gonna move this to the site feedback section since the help threads tend to fit best there.