I go with step three, just ask them, but I only ask for the day and the month, they are so much more forth coming with that! The year isn't relevet and is also the bone of contention for many, unless its a child and then it nice to know what age birthday they are having. Young people are also proud of their age and will happily give you the year. Once people get over 28 they are more reluctant.
A good reminder system just needs the day and month if they are all loaded in as 2007, it doesn't matter. I also use Plaxo as my reminder system and extensively use the Plaxo card system to send a email card out to everyone having a birthday. Plaxo gives me a 7 day reminder in advance.
A person birthday is the most important day of the whole year to them, get that right and you will surely impress them. And of course once you have a birthdate its good for the rest of their life!
I appreciate your work. i have been outting all this into action, but everytime I get one thing sorted, you come up with another idea. I guess that keeps me coming back. I think time will also be my friend here! Did you read Guy Kawasakis blog about his launch of truemors and how quickly he got to the top? whew unbelieveable !