how to keep received data between instances

I need to capture the fact that i got a message which starts up a controller from a specific userid and the time. I am trying to not allow a single user to send a message twice in 10 seconds. Each of the messages starts up its own controller. I probably don't want to write to disk. Is there any Global variable that all the controllers that are spawned can read? I really don't have the language to describe this well.

proof that an old dog can learn new tricks