According to ClickZ, a whopping 97 percent of consumers check their email every day. If you’re emailing donors, and I hope you are, that’s the good news.The bad news, also according to ClickZ, is that (and I quote): 72 percent of consumers state that they have “deleted email from a marketer that wasn’t relevant to me”69 percent of consumers state that they have “deleted email from a marketer because I get too much email from them”66 percent of consumers state that they have “unsubscribed from email that I had opted into because it wasn’t relevant”Clearly, it’s not good practice to send people irrelevant email – or to send them too much.But what does that mean exactly? David Daniels of the aptly named The Relevancy Group offers the following tips. As usual, I’ve added my own commentary for each.1. Segment your audience and messages. Not everything you email is relevant to everyone on your list, so the only way to improve your relevancy is to divide up your list and do the best job you can speaking to sub-groups of people based on their interests. Before you say you don’t have the time for this, remember what Daniels says: “The cost to generate a dollar even from the inexpensive email channel is higher for marketers who do not segment or target their subscribers.”2. Focus on behavior. So how do you know what interests which people? Pay attention to their reactions to the email they get. Are they clicking on certain articles? Donating in response to certain appeals? Use this information to group your supporters according to what interests them, and tailor your content to those groups. 3. Incorporate testing and frequency caps. Set goals for your email campaigns. How many people do you want to open? Click? Give? Now try changing some variables and see if they work better against your goals – like the time of day you send, the type of content you include and the frequency of messages. This can help you determine how much email is too much email – and how much is not enough. I wouldn’t email people more than once a week except in very special circumstances, but your testing will give you the best answer on frequency.For more on email marketing, check out Network for Good’s free resources here.