Here's a breakdown of what it implies:
* No delay: There's no waiting period or grace period. The change starts right away.
* Urgent: The situation demands immediate action.
* Finality: It often signifies that the change is permanent or at least for the foreseeable future.
Examples:
* "This policy change is effective immediately."
* "You are terminated from your position, effective immediately."
* "The store will be closed for renovations, effective immediately."
Essentially, "effective immediately" is a way of saying "this is happening now."