pop-ups and pop-backs: "I thought they can't do that anymore"

See these tweets from this morning:

Penny Farthing ‏@velocipede6                         

Neighbor this am re #40WStNWDC popping up & way back "I thought they can't do that anymore" - historic designation matters 4 #BloomingdaleDC

8:20 AM - 25 Oct 2016