An email autoresponder is a form of marketing automation software. Which automatically sends an prepared email to your mailing list. The process is triggered when contacts fulfill certain predefined conditions/criteria that can either be characteristic (e.g. Certain Date) or behavioral (e.g. Clicks on a certain link). Its very useful in email promotion.
An email blacklist is a list of domains and/or IP addresses blocked from sending emails to users because of spam related issue. There are different kinds of blacklists including internal list run by web mail providers, externals run by security based companies (Proofpoint, Barracuda etc.), and finally another category by non-profit organizations (Spamhaus, SURBL, etc.).
Double opt-in is a system for adding new contacts to your email list . By collecting an email address through a signup form and sending a confirmation email for validation. This is also an opportunity to confirm subscriber consent which is an important for GDPR-compliancy.
A newsletter is an email that’s sent on a daily basis to a list of emails. It can be a promotional email or it can contain editorial content.