Let's see an example. Something close to home. When we, in Gigantt, are about to release a new version, we first release it to our QA environment for thorough testing. This is like a dress rehearsal for the product before it goes live, so there are quite a few steps that must be followed along the way.
This is basically a check list, and we repeat it every time we release a new version to the QA team. But unlike a traditional check-list, all the tasks here are already estimated, their order and dependencies are well known in advance, and each task is assigned to the relevant person.
It's all contained in one big task called "QA Release Procedure":
Whenever we plan a new release cycle for Gigantt, all we have to do is just copy and paste this task into the appropriate place in the plan. In this case, we plop it inside "Release to QA":
So what's new? Copying and pasting tasks is a feature we've had from day one. But now you can also copy and paste tasks between plans. This means you can create separate "repository" plans just to keep track of recipes or experimental plans. You don't need to "pollute" your project's work-plan with recipe tasks that don't really belong there. For example, you wouldn't want these recipes to actually get scheduled by our automatic task scheduler - you want them to just sit there so you could copy them every now and then.
You can also use "greenhouse" plans as a place for very early project planning. Meaning, you can create a work-plan for a new project in its own plan, and not worry about messing up everyone's schedule until you've properly planned and estimated all those new tasks. When it's done, you copy it into the "real" plan in one step.
Copying tasks between plans is the same as regular copying. Ctrl+C puts tasks into your visual clipboard; then you open the target plan (e.g. in a new tab) and paste there.