One of the most overlooked things in mainstream or adult is bulding a list of subscribers. The main reason for building a list is extra income. Not to mention if google changes its algorithim, its good to have a backup source of leads.
So how do we setup an autoresponder for a list? Aweber has a great paid autoresponder that will mange all of your contacts for you. However, I have never felt comfortable trusting another company with my emails, so I found a wordpress plugin
http://wpresponder.com. This can be a little hard to setup but is really great for list building.
Once you have your site ready for subscribers you need a way to get them to signup. This is where you offer them a freebie to signup for your list. Depending on the niche you can often offer a free report or something along those lines. A 5 page pdf book containing information the user is looking for is a good start. I have even used software that was free to download and use (freeware).
The hardest part is going to be sending the traffic that you need to get subscribers. Pay per click programs work well for this, but you can pay an ezine company to send an add to their subscribers. You just have to find a company with a mailer in your niche. You can also hunt down other sites in your niche that have an opt in and ask if they would send an ad to their subscribers.
Handling your list is also very important. You need to keep in contact with your subscribers every week. Its also important not to just spam them to buy this or that. You need to provide quality information and then try a very soft sell. I send three emails a week to my list, and only try to sell something on one of those mails. If you can get your list to have some trust in you they will buy almost anything from you. Its also a good idea to ask for feedback on information you provide them.
If you have any questions feel free to ask.