Now unless you actually go in and manage your Netflix settings, Netflix will automatically set you at "default," which the company claims gives you about "3 hours of TV shows and movies per gigabyte of data." If that works for you, then there's no need to change. But, for example, let's say you have an unlimited data plan and want the highest quality streaming and couldn't care less about gigabytes. In that case, you'll want to go to "App Settings" and then to "Cellular Data Usage," where you can select the option that best caters to your needs, in this case, "Unlimited." You'll of course need the latest version of the Netflix app to make this change. More information on how to manage your data settings can be found here.
All in all, this feature makes mobile Netflix watching way less of a hassle, and as long as you can deal with a tiny Kevin Spacey on that tiny screen, you may start going mobile a lot more often.