You can define different color for every task type, which allows you to better visualize your work on calendars or task lists.
You can also filter tasks list by task type.
If you are an account administrator - you can define task types in Centium account settings on the "Tasks" tab.
When adding or editing a task, you can change its type from drop-down menu below task title.
You can also use task types to mark important events on calendars - like vacations, fairs, company meetings etc.