Bitcoin, Groupon. Everything is a Ponzi scheme.
This actually happens on HN all the time. For example, once one or two people started talking about straw men[1] the entire site decided that anyone saying something they didn't agree with must have been beating up a straw man.[2]
[1] http://en.wikipedia.org/wiki/Straw_man
[2] http://www.google.com/search?q=%22straw+man%22+OR+strawman+O...
Unfortunately most attempts to explain to the general public how U.S. dollars work contain other assertions that are plainly ridiculous (see http://www.youtube.com/watch?v=zXjoAP7jm6Y or http://www.youtube.com/watch?v=_dmPchuXIXQ), and the more tame treatments of related issues lack depth (http://www.youtube.com/watch?v=PTUY16CkS-k).