That's stupid. Google is also walking distance from LinkedIn and had buildings by the yahoo campus as well (tech corners).

You're right, the poorly implemented copies of Gmail features could just as easily been written by Xooglers, but it's a funnier and longer-standing joke that the entirety of LinkedIn is as a hodge-podge of other peoples' ideas.

Google and LinkedIn are swapping buildings, so that will no longer be literally true when the swap is done. But I agree that it's a silly thing to say; Silicon Valley companies do swap employees all of the time.