New user signup

Is membership of an internet service on IC intricately dependent on membership with Dfnity, in the sense, does having to become users/members in an open internet service we develop require users to be prior members of the Dfinity Internet Computer platform? We ask because the LinkedUp video’s demo showed the developer using existing members on the Dfinity platform.

Services running on the Internet Computer can identify users by a Principal id that gets passed to the their public methods. You can generate these for any of your users in your client software or web frontend etc., users wouldn’t have to sign up for them anywhere centrally on the platform.
You can see how this works in practice here: Add access control with identities :: Internet Computer