I second that.

[Britney]

a phrasal sentence that means, when taken literally, “I echo that statement of yours.”, “I echo your above statement.”; “I agree with you [100%ly].”; or simply “[Ditto].”. See also [I second that emotion].
Phrase used frequently on [message board]s (more so than in person) by someone usually immediately after someone-else stated something with which the other person agreed.
Note that the word ‘[second]’ is being used as a verb in this sense, and is derived from ‘[2nd]’(as opposed to the length of time).