I just discovered that putting your cups against the electric watter boiler heats them just like the top of an espresso island. Preheated cups and plates are nothing new of course. Hot coffee or hot tea looses some of it's heat when poured into a cup. And it also gets cold over time. The feeling it is a hot drink increases and it stays hot quite a lot longer.
It's as if it's loss of heat doesn't work half as well as one would expect. In stead of the content starting to cool down and loosing it's warmth straight away it now warms the table it stands on. After finishing the drink the cup is still just as hot as it initially was.
By creating a warm zone around the hot zone the heat appears to flow far slower out of the hot zone. Imagine it like a sand hill eroding away in the wind. If the hill is steep it erodes away much faster then when it has a slight slope. The same, if the area where the heat has great height drops down to an area where the heat is really low the peek of the hill flattens rapidly.
This is of course besides from the logistical sense it makes (to keep the cups there).