Click on the “All Threads“ drop-down, and you can filter the view so that you only see questions without answers (if you're looking to help out others) or questions with answers (if you want to browse for useful information).
If you find a post that answers a question of yours, click the “Yes“ button next to Was this post helpful to you? in the preview pane. This stores a property on that item to indicate it was helpful, and the more people who do this, the better - you're helping the best posts float to the top. You can also select “threads with helpful posts“ in the view filter so that you only see those types of posts.
Click Notify me of replies in the preview pane to get an email when anyone replies to a specific post.
Click on the poster's name in the preview pane to see their profile (if they've filled it out).
Click on the button to fill out your own profile (it does require signing in to passport).
Over time, the data will get richer and richer as posts are marked helpful.
Update: Also see this site, which doesn't have the additional left-hand menu.