The fastest is blog commenting. You can use software to automate (not spam) some aspects of blog commenting. Forum posting is probably the next fastest.
Joint venture partners are a good one to look for. If you find someone doing a similar product/service to you, then talk about link exchange, list swaps or mutual promotion. Combining this with the fact you can then swap partners with your partners, you can get an exponential traffic explosion.
I have heard about micro blogging and CSS submissions to bring traffic. Does anyone know about it? If yes than please post here.
this is my first post here on the forum after mentioning all i think there is to mention for driving free traffic i could not see where it is mention of the use of "website syndicated content" this is a great resource magazine for driving traffic that is 10x faster than ezine or any other article directories you can imagine.another name for it is interactive magazine! works splendid!!!