Wrong! It isn’t “I could care less” – it’s “I couldn’t care less!” If you miss out the “couldn’t, it actually means you really care a lot… and mostly it isn’t used in this context.
This phrase really annoys me, it is abused so often. It’s a joke. And yet people – mainly Americans right now but I am sure it will spread – people keep on getting it wrong, time after time, in comments, on fora, mostly on the internet.
I could care less… but then I wouldn’t be so passionate about it!