Many believe it is being enabled by VoIP technology, which has made calling long distance cheap.
The FBI is reporting:
It’s one of the latest breakthroughs in telecommunications—Voice Over Internet Protocol, or VoIP, which enables telephone calls over the web.
And guess who’s hopping on the VoIP bandwagon along with millions of legitimate customers? Criminals, that’s who. They’re using the technology to hijack identities and steal money. It already has a name: “vishing.”
FBI vishing warning, here.
The term vishing comes from phishing, which is still a growing problem. The Anti-Phishing Working Group tracks phishing statistics, which go up (it seems) every time they issue a report.
I've yet to see any statistical analysis on vishing, but it seems to be a growing problem, also.
Legitimate companies don't contact people (unsolicited) and start asking for all their personal and financial details.
Vishing can be reported to the FBI, here.