Not trying to be a downer to your article here, but that article mainly targets 3G phones and connections. These free apps use roughly 10-30kb of RAM and occasionaly access wi-fi (unless disabled). Our batteries may drain from excess applications, but not in the same context as that article.
Word of advice: check out the update/wi-fi settings on all of your apps. No need to fully uninstall. Also..."free" has nothing to do with the resources an app will use. Background wi-fi use from a paid application is likely to use more power than loading an ad from a free program on startup.
A new App at B&N is "Your App Manager" for $0.99. This handy utility allows you to "kill" Apps that have a persistent utilization of your RAM and in some cases activation of Wifi and other links. You can not stop any function that is required by the Nook and all the Android functions have the Android Icon so you are not likely to close anything your Nook needs. Apps listed as "Memory Unknown" are not currently active, any other entry is how much RAM the App is using. I have found Apps that I use only once a week or even less are still active in RAM. With this App I simply "kill" or close them. They open just like normal the next time I tap their Icon.