At the user homepage you can see a list of all your topic, change topic properties such as sharing mode and topic name, and search for topics by keyword.

Each topic is defined as either Private, Shared and Public. A private topic can only be viewd by you. A shared topic can be viewed by you and people on your buddy list, and public topics can be viewed by everyone. To change sharing mode, click the "edit" link next to the topic name on your topics list.