XenForo v1.1.3 Features:

Social Engagement
Keep your users coming back by letting them earn trophies for reaching milestones. An intuitive “like” system makes users feel appreciated for their contributions, while integration with Facebook allows easy registration and sharing.

Recent Activity Stream
Allow people to easily see all the recent happenings on your forum, beyond just the messages posted. Members can follow each other to get their own personalized news feed showing the content they want to see.

Alerts
Make it easy for users to stay up to date with updates that are applicable to them. They’ll receive alerts when someone quotes their post or responds to a status update, when they receive a new trophy, and more.

Easy Styling
You can use XenForo‘s simple color changer to easily change the look to suit your needs. You can make further changes through an extensive style property editor, or edit HTML and CSS in your favorite editor. No code changes necessary!

Great Add-ons
XenForo is built to be the most extensible and flexible community software ever. Check out the huge array of add-ons already available in the resource manager, or get help writing your own add-ons with the XenForo framework.

SEO Built-in
With XenForo there is no need to pay more for your search engine optimization needs. Human-readable URLs, semantic HTML with embedded microdata, and many more SEO features are present in the very core of the system

Demo: http://xenforo.com/

Download XenForo v1.1.3