i like squidoo...if you have worked over you lens good enough to have it ranking high on squidoo, that can bring to your site many visitors..
I think this question would be asked in different way. HOW CAN YOU USE SOCIAL MEDIA TO BRING TRAFFIC.
I'm use FB. Facebook is a fastest-growing popular online platform that enables customization of user interface, which also includes installing applications to personalize the experience further.
StumbleUpon has a huge boost, but it doesn't last too much. Anyway, it's the most useful for traffic needs. Digg effect is less, but it lasts more.