i'm not sure whether its possible to get a real opt-in email list. cause when people opt-in for a newsletter or for some service, there is usually an agreement which prohibits selling or distributing that email list. it woould be a violation of privacy to sell or distribute a real opt-in email list
buying so-called opt-in emails are a no no.
usually if you see these sources they don't want to divulge where they got their email addresses in the first place, mostly they harvested it on google and on forums.
I actually just found out about that a few hours ago. I didn't know it was considered spamming, esp. because I assumed people who added their contacts to the list are allowing 3rd party ads...
you can advertise on so-called opt-in newsletters there's no problem with that, but to call them your opt-in ads is not right, it's their opt-in ads and it cannot be sold, what they can sell are ad spaces on it not the emails itself.
most lists that you would buy would not be very high quality or you would not be sure of exactly what you are buying, your best source would be to collect them from your own sites as then you are 100% sure they agree to your terms and are actively interested in the subject matter of your products, 2 solutions out there to help among others are http://www.constantcontact.com/ and http://www.topica.com which both offer free trials I believe.
I didn't know it was considered spamming, esp. because I assumed people who added their contacts to the list are allowing 3rd party ads...
