2 quick questions...

[Livealarm 474]

What are these stars? And why some of the stars are blue and others are white?

And also, what does this button do? 

[Totally Nyx 36,032]

The star signifies that it's a thread you've posted in before. It's lit up and highlighted in blue if there are new posts in that thread since last time you read it, or rather since the last time you viewed the last page. Otherwise it's a faded gray star.

[Silly Druid 6,963]

2 hours ago, Livealarm said:

And also, what does this button do?

That button is for 'code', which means it will display text in a way that every character takes up the same amount of space. This is good for posting programming language code, as well as other things, like ascii art.