This has been discussed a lot on FT. My opinion? It's a mess created by two problems:
1) US and European MC/Visa units not operating with effective communication
2) Focus on policy and not on practice (per policy, a US card without chip should be accepted even at a pay-at-the-pump station. In reality, it may not work.)

Previous discussion includes:
http://www.flyertalk.com/forum/other...-chip-pin.html
http://www.flyertalk.com/forum/ameri...chip-card.html
http://www.flyertalk.com/forum/other...magstripe.html
http://www.flyertalk.com/forum/air-c...n-what-do.html
http://www.flyertalk.com/forum/trave...hout-code.html
http://www.flyertalk.com/forum/trave...ds-europe.html
http://www.flyertalk.com/forum/ameri...-chip-pin.html
http://www.flyertalk.com/forum/ameri...travelers.html