Project as a Label
Individual tasks can be labeled, and a Project can be used that combines the Labels. For example, I can enter a task "@jobsearch Update Resume with Language Skills" into a "Next Steps" Project and also be able to create a "Job Search" Project that compiles all of the @jobsearch tags. This is equivalent to having one task filed under multiple projects with the added feature of being able to create a project and populate it with tasks based on the labels.
In order to browse all tasks based on the label, please try to type @jobsearch into the search box and you will see all tasks across all projects that have this label.