Thanks. I did know that the multitasking/long press of the home button would bring up most recently used apps, but my understanding was this was independent on whether they were "running" or not. It would be good to know if swiping an app closed from this list really closes the app, or if it just removes it from this list.
I'd seen an exit option on Pandora via a context menu (when using my wife's Android running 2.3) but so far I haven't come across another app that had this option, but I haven't downloaded all that many apps for her phone. It's good to know that Opera has an exit option, as the browser is one of the main items I'd like to make sure to close for privacy/security reasons.