Ask HN: Facebook Connect, Own User Sytem, or Hybrid User System

I am going to launch my new website very soon - Trakable.com. Then, I stumbled upon Facebook Connect. The whole concept of Facebook Connect is really amazing. I am thinking that whether I should embed Facebook Connect into it so that it could benefit from the social graph of Facebook.

If I embed Facebook Connect into my web application, it means that my whole user system will solely depend on Facebook Connect(I believe that very few people will actually register through my User system if there is Facebook Connect available). So, if Facebook changes the policy, it may ruin the whole user system of the website.

Any suggestion?