Thanks for the answer, Gerard. In general, what Gerard says is true and is a good rule-of-thumb. However, in the interest of full disclosure, I'd like to further clarify because it's slightly more complicated.
The owner of a report can schedule delivery of a report to any active user.
If you are not the owner of a report, but you have access to it, you can still have the report delivered automatically. In this situation, you will only be able to select recipients who have to the application in which the report was created. For example, if Bob creates a report in the Analysis application, but you (John) would like to schedule delivery of that report, you may choose any user who has access to the Analysis application as the recipient.
I hope that helps!