gistfile1.txt

a) Show every 14 days:

{
  "popup_mode": "auto",
  "auto_interval": "14",
  "popup_id": "does_not_matter",
  "url": "http://..."
}

b) Show once:

{
  "popup_mode": "once",
  "auto_interval": "14",
  "popup_id": "campaign-dec-2014",
  "url": "http://..."
}

c) Show every time (NOTE: popup_id must be empty):

{
  "popup_mode": "once",
  "auto_interval": "14",
  "popup_id": "",
  "url": "http://www.sikhnet.com/fundraiser/2014/general3"
}