Which one is better, twitter or face book for increase site traffic ?

Hi Everyone,
I have account on twitter and face book and I have almost 3700 followers on twitter and now recently I created account on face book and I have almost 50 friends on face book. Now I want to use these sites for traffic purpose. So please suggest me which can be most effective for traffic purpose.

Thanks in advance for your opinion!

I think facebook is the great source of traffic.You can get traffic from FB by engaging more in different discussion,by making friends.However whenever you update your site you can post that link in twitter and I hope some people from your around 3k followers will come to visit your site.