Your plan is limited to certain number of contacts, but what is counted as a contact here?

In short: A unique email address you can send marketing to.

Each unique email address creates a contact within Loyalistic. It's case insensitive, thus it does not matter whether it's written in upper or lower case.

In technical sense, you won't have duplicate email addresses.

However people might use multiple email addresses or have multiple domain names or email aliases connected to the same mailbox. Each creates separate contact. There is no technical way to detect which belong to the same person and which are a different person.

The next thing is whether you can send marketing to the address?

You can if the contact belongs to at least one list, the contact have not banned marketing, and the address is still working. If the delivery fails for a permanent reason, the contact is blocked and omitted from further attempts or campaigns.

So if you want to see if a contact is NOT counted, check whether ANY of the three conditions are met:

  • Hard Bounce: Blocked because of a permanent technical reason
  • Marketing ban: Marketing set to No
  • No lists