You may notice a new icon in the forums list.
This check mark means the topic has a solution. When you click on one of these topics you will see a link.
This will take you to the resolution for the topic.
When one of your posts is resolved you can mark it resolved by clicking on the menu for a given post
Once the menu expands click the checkbox.
This will help future users (or yourself looking back) with the same issue find a quick solution.