Thread topic - Bold vs. Normal

I'm just curious: Why is it that some thread topics are written in bold and others are just normal?

Thank you!

 

I think the threads which u viewed once become normal and unview ones are bold.
Hope iam not wrong

 

Yes, new threads that you have never been in and never have marked as read are bold. Those you either once read or marked as read stay normal.

EDIT Having said that, I think it's not true. I'll see if I can dig out the official answer.

http://forums.digitalpoint.com/showthread.php?t=62028 is the official answer.

So there's 3 states. Bold, Slightly Bold and Normal.

 

Thanks for your help everybody!

Dude! No way!