Members can start threads once they have passed the 75 post threshold.  Lurking is a great way to get to know a forum, but there are always nuances of any community that you won't really get until you begin to participate.  It's a way for new members to settle in and acclimate and hopefully get a feel for what kind of topic warrants a new post before creating them.  

New members can start threads right away in the SOTDRT forum.  Mods csn them move them to the relevant forum.