Yes. In common with best practices, and to prevent others maliciously joining members to the list, all join requests now require confirmation from the proposed member prior to the membership being activated.
This facility is often known as "double opt-in", i.e. not only must the user request to join your list, but before they actually become a member they must also reply to the confirmation request. If they do not respond to the confirmation request they do not become members of the list.
You may if you wish disable this requirement under the Access > Join page.
Keywords:list communicator new join double opt-in