A safelist is a group of online marketers who agree to receive ads from one another. For the privilege of sending your advertisement to them you reciprocate by receiving their advertisements. So for your advertising message to be sent to them you in return will get hundreds if not thousands of emails in return.
Your email messages are not considered as spam as all the members of the safelist have agreed to receive your emails.
You sign up for a safelist, you send out your messages. In return you get hundreds of emails back. When you realise you do not have the time or inclination to read them all you begin deleting them without reading any. But guess what, the person(s) who received your emails are doing the exact same thing. Trying to sell to sellers has an inherent fault.
Safelists offer a range of classifications from free membership to paid membership with a whole range of subsets in between.
Paid safelist membership (from my experience) achieve no better result than free memberships.
If you are on a free membership that allows you to mail once every so many days, get off it!! You are only working for the list owner because you get up to seven days of emails in return you only send once. You get nothing for your membership, just waste your time deleting emails. In fact you are working for the list owner helping him build his safelist. If you are going to be a free member sign up to a safelist that allows you to email daily.
Earn credits based safelists are a huge distraction you can do without as you waste time opening emails to find or collect your credits. Or some people only sign up for the introductory free credits when they are used up they quit the safelist and look for another. These safelists in reality are no more responsive than the other types.
Safelists come and go all the time.
If you want to find a safelist, enter the word safelist in a search engine.