Not sure one could call it a data structure but who remembers the so-called Sneaker Network or Tackie Network, which consisted of someone copying information onto a disk and physically walking to the other machine to copy the information. Networks were so slow/buggy that it was often quicker to transmit information using this "data structure"
Frisbee-net is more efficient then sneaker-net in open-plan environments. A trained professional can deliver a 3.5" floppy to its destination, and catch a return packet, with remarkable precision.
(though ohyes is right: these are transport layer methods/algorithms, not data structures)
Yes the Floppy disk is the Data Structure, which is interesting in itself, but in order for this data structure to work it must be both loosely and tightly coupled to the transport layer....
edit: To the downvoters - is a sense of humour not allowed on HN?
If you're going to try to be funny, at least include it as part of an otherwise worthwhile comment, otherwise it just adds noise to the discussion (and encourages more of same). I know HN seems kind of neurotic about this, but we're trying really hard to keep away trite "first post", "[citation needed]", etc. comments, and given HN's age, it actually seems to work.
Then I don't get the joke - it just sounds like you don't know what a data structure is. (I don't have downvote-superpowers, just offering an explanation)