Learn English – “Thanks” or “thank you”

I'm not sure what "thanks regardless" is supposed to mean.

• Thank you, regardless of whether you can help me [in the future]: the better way to say this is "Thank you in advance" or "Thanks in advance"; but given that that's what you wrote at the end of your question, it seems you believe "thanks regardless" means something else.

• Thanks anyway: this would definitely not be an appropriate close to a message. You would use it if someone had just said "no" to a request, and you wanted to be polite (or wanted to appear to be polite).

Edit: thanks for the link. I've looked at the query which prompted this question, and given that context (asking a question and then finding out something which makes it moot) I actually think "thanks regardless" is an OK phrase - as in, it's grammatical and it makes sense. However, I think Remou's suggestion of "Thanks for all the replies" is more polite.

_{[Note that Stack Exchange etiquette doesn't require, and possibly even frowns upon, conversational noise such as "Thanks in advance".]}

I agree that "thank you" is slightly more formal than "thanks". I suspect if I was addressing the Queen I'd say "Thank you, ma'am". I tend to use "thank you" for emphasis, to show that I am really grateful, and it's not just a polite formality. Otherwise there's not a great difference, in my opinion of common usage. (Except for 'giving thanks', but that's a whole other kettle of fish.)