How much traffic you are getting from Facebook & Twitter and what strategy you are following to target these social network? Also post your Facebook, Twitter & Linkedin profile here so that interested member can follow or connect with you.
Facebook is helps you to get traffic because it is the best social network. It has got over 300 million monthly active users which is more than any other social network at present. These stats are the proof for Facebook being the best social network for maximum traffic. You can target your desired audience by defining accurate demographics of your audience. Here you can find people of all ages. You first advertise your website on Facebook fan page for minimum rates and create your website's Facebook fan page side by side which will help you to drive Facebook traffic to your website.
If you have blog you can link it to twitter and facebook account so that any updates are triggered. Twitter account also can be linked to facebook. If you have many friends or follower, that would be massive traffic.
IMHO, Twitter is not a great tool to drive traffic but it's an awesome tool to communicate with other bloggers who are willing to comment your post, vote for you submit and even link to your blog.
It is my understanding that the developers/owners of both sites hate their sites being used for traffic gain and actively attempt to stop it, so it has also been my experience that gaining traffic from both sites is getting more difficult. I have managed to get a few active sign-ups from non-friends on FB which has been nice but as a traffic source it is not the best. Only my experience though so don't rule it out