What does the green circle that appears next to all my posts mean?

The green circle is a reference to how many posts you've made to this forum. A green circle (beginner) means you're fairly new to the forum and have made fewer than 25 posts. Once you've made more than 25 posts you'll be identified by a blue square (intermediate). With more posts you can become a black diamond (expert). You may notice other posts identified by a Ski Patrol symbol. These users are Forum administrators or moderators who are responsible for monitoring the forum.