Are you referencing the font in the posts or the title when you view it in a forum.
The font is user selectable The title (of any thread viewed in forum) is bold when unviewed by you and regular font once you've clicked on it to read it once. This is an organization feature so you don't have to remember what you've read.
It can take a while to build a following. My suggestion would be to post in the journals of people that are frequent posters, and also to enter a photo in one of the monthly contests. This will help you become known.