The article states: "Once the Earthing pad is connected, it must touch a person's bare skin in order to be effective."
This is not really accurate in a strict sense. You might get more benefit from touching the pad with bare skin, but the effect can be measured through clothing, and/or with a bed sheet between your body and the pad. A muti-meter will show whether you are grounded or not, and the extent.
Staying grounded at night (and maybe even during the day) dramatically improves sleep for me. It is something I take with me when I travel, and that says a lot.