Few web sites really need your birthday, but that doesn't mean tons of them don't require you to enter a birthdate when you're registering for an account. Reader Michael isn't a big fan of sharing his private data unnecessarily, so he suggests this simple solution:
When I register online for websites that require a birthday, I select a date other than my actual birthday. I reuse this date for all websites where the date is required only for security or demographic information (anything associated with credit report excluded: banks, utilities, etc.). To make it easy to remember [your un-birthday] , retain [your birth]year, but change the month or day. That way the demographic value and security control retain validity while you protect your true birth date in the event the website is hacked. Ex: With an actual birth date of February 29, 1990, I would select as my "official" un-birthday April 15, 1990 (selected in this example because it's Tax Day in the US, easy for me to remember).
Don't forget to document this change in Keychain, KeePass, or other password manager should you use it.
If you're born in the first part of the month, an easy way to do this is to swap the month and the day -- so December 1 becames January 12.