Use of RFID for credit cards seems to be mainly (for now) a US thing, but there are many other uses for the method, for shipping, stocking, and other inventory control purposes, and for access identification for places where public entry is limited. A concern of some is that it isn't always obvious when the devices are used for some of the more subtle purposes.
The Wiki article already linked implies significant use in several places other than the US, that might not come readily to mind except among the smaller groups of people who use them. A particular kind of use in lots of places is described within the same article at Toll Roads, although several other "popular" ones are mentioned elsewhere in the article.