I wrote a blog post about Twitter sending over 3k visits to my wife's new blog - it took her some common sense, and a single Tweet. Oh, and some luck, too.
It's all in who you know and how you approach them. I've also leveraged Twitter to grow my audience and make direct and indirect sales, in a passive way, using Twitterfeed, MarketMeSuite and Paper.li.
I'm experimenting more w/non-Google traffic in 2012, since SEO sends me 80-95% of my traffic so far - but when I started TheAverageGenius.net I solely used CommentLuv (with various other blog comment linking) - mainly as a social tool (whitehat) and not automated/SB stuff.
Anyhow, guest posting has also sent droves of traffic whenever I bring myself to do it, and creating a PDF with an embedded social sharing button (Twitter) helps, too. I didn't distribute it yet to PDF sites, but use it as a back-end way to gain customers to my Duct Tape SEO book - seems to work. Nothing major yet, but it's passive income, have made nearly $4k with the book (launched around August or Sept of 2011).
Someone that I've been reading a ton of on traffic is Kim Roach with her Traffic Dashboard (and her free Traffic Underground PDF) - pretty much all new ideas to my SEO brain. Where I first came across Charlie Page (haven't used him yet).
The blog post of my wife and Twitter:
Edited by DuctTapeSEO, 08 January 2012 - 14:14.