Electronic debits, ATM deposits, etc,... anything where an entry has been made but the funds not verified, is usually seen as a memo posted transaction. The bank has been notified of the transaction but the funds have not actually been transferred, verified, or actually posted to the account.
Example: You make an ATM deposit. Yes, the money is in the envelope, the envelope is in the bank's ATM, and the deposit shows up in your account almost immediately. Problem is they won't collect the deposits from that ATM until tonight, after which they will go through them and verify that the amount you punched in matches the amount in the envelope. The bank has been notified of the transaction, but won't have verification of your deposit until later. That's a memo posted transaction. They have a memo that says you did something, but have yet to verify it. It is, quite literally, an electronic sticky note saying an amount has been debited/credited pending formal verification and validation.