Thanks for your visit first and I'd like to share with you some of the new exciting features you will find in the upcoming V4:

1. Social Network (Facebook, Twitter) Sign In Support;
2. Featured Articles Slider and Search Everywhere;
3. Search Engine Remake

You can also find other features we planned for version 4 in Forum News.
 
For the current v3.9, you can view a live demo here.
 
Also, see the point below for detailed instruction on Integrating the Forum with your own Membership System!