Do not email
Everyone your sends skip, why, and which of those you can undo.
EmailEmail → Do not email lists everybody a send will skip, under four reasons that are not the same thing. Unsubscribed: they asked to stop, and only they can undo that by signing up again. Bounced: the address does not exist — sending again damages your standing with the provider. Marked as spam: they pressed the spam button, which Gmail and Yahoo count against you directly. Suppressed by you: somebody on your team added them.
doTask has always honoured all four — this is the page that shows them. Nothing about your sends changed when it appeared; you can now check why a particular person stopped receiving things, instead of wondering.
Adding addresses: paste them in, one per line or comma-separated. An address we have never seen is created already blocked, which is the point when the list came from a previous tool — those people must be unreachable before they are ever reachable, not after the first send.
Taking somebody off: only a hand-made suppression or an unsubscribe, and only deliberately. A bounce and a spam complaint cannot be undone here, because the first is an address that does not exist and the second is the mailbox provider’s verdict on you. Overriding either is how a sender ends up in the spam folder for everybody else on the list too.
Export CSV hands the whole list to another tool — worth doing before any migration, because a suppression list is the one piece of email data you can never rebuild.