I experienced endless frustration trying to use my UK-issued international dollar card for internet transactions. I tried the secondary address option and had a lot of contact with AmEx about the entire issue, never getting a satisfactory resolution.

It all depends on the merchant's side and how they have set up their verification rules. Some online merchants have very tight controls and require a precise address match; others are more lax.

I fnally gave up and got an extra AmEx using my U.S. address for those transactions.

Susan