If you haven't written anything to most of your list in a long time and you have a new product launch (I'll use fishing for an example niche), do you think the first email subject should be something like, "Take a sneak peek at my new program Fish Master...." or something like, "The best places to catch blue fish".
I think I'd warm them up a bit with one or two emails that remind them who you are. Maybe even give them a few tips as well. Then hit them with the new product.
I agree with wulfster, you have to show them that you can really deliver good stuff! You can definitely make more sales if you prepare them for it, rather than dropping an e-mail at random.
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