Tarsnap has a "are you Canadian" checkbox. Unfortunately if you are Canadian I have to collect your name and address because I have to provide[0] invoices/receipts which contain this information.
Mind you, there's no requirement that you give me truthful information. If you claim to be John Smith living at 123 Main Street, you'll get an invoice which says that at the top of it. You won't be able to use it to claim a tax rebate; but if you're not running a business it's not useful for that purpose anyway.
[0] IIRC I technically don't have to provide those such invoices to everybody; merely to anyone who asks for one. But collecting the information up front and emailing PDFs to all the Canadians is much easier than handling individual requests later.
That's what I had thought. However, users will lie about a DOB if they will lie about an age.
If it's a user experience thing, fine, but at least make it an optional field.
On my small business we ask only for an email address, password and confirm password. Everything else is excessive.
Tax obligations can be another problem which may require an address, but often have a simpler way to resolve them by simply picking the appropriate country and state off a list or even with just a checkbox for "are you in X jurisdiction which I am required to tax?". I believe Tarsnap handles it that way.