I have had great luck promoting my articles and such by using social networks and social news directories such as Digg and Reddit. Several of my articles have gotten over 100k of hits from promotions such as these and it didn't cost anything but the time invested in writing the article and posting it, and with Digg the time necessary to build up 1000 friends, back when that worked well.

Yea social bookmarking really helps but have you ever thought on Video marketing on YouTube and such.?