Just because someone is your customer doesn't mean they want to subscribe to your electronic newsletter. Nevertheless, you can dramatically improve your subscription rate if you provide newsletters which are perfect for the device your audience uses to read it. For instance, if your readers are using older displays, then having a narrow format is crucial. If your readers are very mobile, they may be reading on a Blackberry and prefer lists of text links to images and paragraphs. NextStage Evolution has just completed major research which says although relevancy and cultural connections are important, the ability to match the information portal comes first.
MarketingSherpa: How to Design Your Newsletters, 2008-Jan-30 (interview with Joseph Carrabis)
The Information Portal -- where people read your messages -- has the biggest impact (36.7%) on whether they take the action you desire. This chart underscores a key idea that recent EmailSherpa articles have highlighted: Surveying your list to see what type of device readers use to view your email is definitely worth a shot. That’s right: viewing on an iPhone, a BlackBerry, a Mac or a PC affects how they will be influenced by your message more than any other factor. Being able to segment your list according to receiving device could be a boon to your response rates.