The true answer (right now running on my head) is Either u have to invest in marketing and advertisements OR u shud have patience and time to create a really useful blog|site that can connect people of similar interests or atleast make them come back once in a while.
I m also still trying to discover the key to enormous traffic!!..Gud luck!
Facebook -> Most people just click the 'LIKE' button and hardly come back.
Twitter -> People these days rarely click other's links unless they think its worth clicking. They will instead just follow and leave it that way.
Bloggers|Similar Sites => We are more concerned abt voting, commenting & pushing our talks with more replies....Do people really go to my profile after that and click my blog post?? At most, people will just vote and follow...they wud rarely visit ur posts since they are more focused on their posts.
Google is the king! Run after it. Try getting on the first page of Google. U will win half the battle even before using all other services...
Yahoo gives probably 10% of what google brings to my website. Maybe its because most of the locals here uses google. When I was in Vietnam, I learnt that most of them use Yahoo. People use Baidu in China and are unable to view Youtube.
I guess it good to find out whats popular amongst your market segment to generate more traffic.
I really dont know other tools (which means i dont think its worth investing time on unknown or not so effective tools) I used facebook & Twitter BUT 90% of my traffic comes from Google itself. 10%, i dont know may be facebook + Tweets + bloggers I recently started on bloggers.com else Google was only my focus (and i quit facebook & tweeting)