I have used Constant Contact in the past for my business and for clients. If you email regularly and with high volume, it is a good idea; Constant Contact allows you to easily track lists and offers options for 'opt in' or 'opt out. Work with their rep to get the best deal because it can get expensive if you don't pay attention to your numbers. Also look at Mail Chimp and Infusion for other options. Good luck!
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