More and more, mobile phones are the way that information is going to be received, and absent having a mobile option for response it's going to be more difficult to get a timely membership response. For example, with calls to action and membership surveys - where members either do it when they read it or they may never go back to it.
Today, in ordering "Maine Day" tickets to an upcoming Red Sox game, one of my ticket options was to receive "mobile tickets". The scanners at Fenway Park can use the image on a cell phone. At my daughter's college, the washing machine and dryers can send students a text message when one is available for use, or when their laundry is done.
I know many associations are reluctant to use text messaging features (for mass message delivery) because there's no certainty we won't create a charge to the members who may not have unlimited text plans; or because we haven't really thought about/planned on how to give mobile options. But as more and more everyday activities have mobile options, it's going to be expected.