Email List
An email list is a stored group of email addresses you send to. The consent behind each address decides what you can send to it.
An email list is a stored group of email addresses, usually kept in an email service provider along with the consent each person gave. Whether you can send marketing email to it depends on whether those people opted in.
Buying or scraping a list does not establish the permission needed to send marketing email to it. Google’s sender guidelines tell senders not to purchase addresses, and in some jurisdictions sending marketing email without consent is unlawful. Under Canada’s CASL, for example, the sender must be able to prove express or implied consent.
Size versus quality
List size alone says little about who still wants the email or can receive it. Review how addresses were collected, subscription preferences and delivery failures as part of email list hygiene. How people join matters too: double opt-in asks the recipient to confirm the subscription, while single opt-in adds contacts without that confirmation step.
Common mistakes
Measuring the list by count alone. Importing addresses without recording where and when consent was given. Sending the same email to everyone when segmentation by signup source or activity would let you send less to people who want less.