I always cross my fingers that they say an actual number, but a surprising amount of people (and companies) have NO WAY of capturing people’s email addresses, or (equally as surprising), that they do have a list, but they have never sent a single email to the people on it.
Here’s what is wrong with both of these scenarios. The whole purpose of having a blog, or Facebook, or Twitter, or really, anything where you interact with people is that you’re trying to build up an audience of people who are interested in your work. You’re not trying to trick anyone or be a slimy salesman, ok? You’re just collecting names of people who like you/ like your work and who will be happy for you when a new book comes out. These people will go to the trouble of opting in to a mailing list if you will just give them a chance. You should give them that chance!!
Marketing people commonly say “The money’s in the list,” and this could not be truer for authors. This expression just means that if you build a targeted list of people who buy one type of thing, you are most likely going to be able to sell them related products in the future. Whether this means you sell soap and you sign people up so you can let them know when you have new soap, or you make money through affiliate marketing by reviewing software for an audience of people who are interested in software, having a targeted list is super important, and it’s something you should definitely be doing, because really, you/ your work is the product here, and your list
The other reason why you should be building your list is because (as Tim Ferriss will tell you), having a large list of people who are interested in buying things you write is the quickest way to get your book to go to # 1 on the bestseller lists on the day it comes out. When you build your list and communicate regularly with its members, they will WANT to help you make your book successful.
If this is something you’ve been putting off, I think it’s something you should do today—really! Try MailChimp. Take a look at Aweber, Campaign Monitor, and Constant Contact. Keep trying things until you find something that works, because these days especially, an author is only as successful as their list.