Couple of months back I had created a post on Aweber Vs. Getresponse in which I finally decided to go with a desktop based mailing client. I was pretty happy with it but I wasn't ready for (and didn't anticipate) one thing - Spam complaints. Few days back I sent an announcement to my list and I was surprised and shocked to receive an email from my SMTP server webmaster that they has received couple of spam complaints and this would be the final warning. They wanted proof of subscription requests, which I didn't have and thought won't be necessary as I used a double opt-in mechanism. It was my fault too as I had not be in regular touch with my subscribers and people seem to have a very weak memory nowadays. That apart, if you are not using a hosted solution, which means you are using a script on your server or a desktop software, it is critical that you maintain copies of all email requests. Now rather than making users click on a confirmation link, I ask them to reply to the confirmation message. This way, in case of any complaints, I have a valid proof of the request originating from the user inbox. Yes this is a bit of pain and also increases processing time, but when you want to save monthly costs associated with hosted solutions, you need to do the extra work.