You'll definitely want to considere Double Opt-in list building if you are starting to get spam reports. For Those who are new to list building, an are unfamiliar with single opt-in or double opt-in. A single Opt-In Subscriber gave their information once, but did not comfirm from the e-mail account that they themselves did indeed give their information.
There are some key reasons you'll seriously want only these kinds of leads. For one, you know This person has a real interest in what you have to offer. If a person only opt-in once (single opt-in) Than they could potentially be giving you someone else's information. Placing you in danger of getting Spam reporting. IF you have an account with Goddard for example, they could cancel you domain Name if they receive enough proof that you are spamming.
Beside the hassle of receiving spam complaints, you whole purpose is to build a responsive list Not just a bunch of name. If you are in the homebased business field you want pontential internet marketers, not bycicle lovers.
You'll attract Joint Venture partners, it's not the same to be able to say I have a double opt-in list 10,000 of subscribers. At this stage you'll be considered a real player. Yes, there are people with hundreds of thousands but, 10,000 double opt-in is pretty good.
Going back to spam complaints, if you get a high enough spam complaints the major ISP(internet service providers) could band your domain and you'll be blacklisted, and that something you'll want to avoid at all cost .
One such company who is well known for having this feature as an option, which they highly recommend is Aweber.com. They are comfirmed autoreponders, or whitelisted with yahoo, hotmail, AOL. So you'll get at least 97% delivery rate to the subscriber's inbox and not in the spam folder.
If you are doing your research to make money online you'll need an autoresponder. Having a high quality autoresponder is a must if you are serious about building a double opt-in list. One with double opt-in option so all submission will receive a comfirmation e-mail with a correspondent link.