Make a campaign on microworkers about "Post my Link On Relevant Forums". Currently Micoworkers has about 850.000 freelance workers worldwide. You know that posting a link on Forums is not that easy. There would be thousands workers out of your campaign after they're trying hard the get a forum that accepts a link within their post. But the benefit for you is that they have visited your link to understand your site to search a relevant forum for your link. On this campaign you only accept real clickable link on forums. From about 850.000 there will be ten to hundred thousands freelancers who are interested to work on your campaign "if " you make a long lasting campaign(s) by hiring at least 200 posisions and teasing among 850.000 workers by paying $0.30 - $0.50 once one successfully posted your link on a relevant forum.
I am actually using a free service called Cloud:flood created by Glen of the ViperChill. I had great success with it, making a file available for download (I shared a list of 140 blogs worth following). It has two options, a person can RT the download that will take new people to a post where the download is (or what ever landing page you want them to come to) or they can share it on Facebook instead of tweeting it.
The term “organic traffic” is used for referring to the visitors that land on your website as a result of unpaid (“organic”) search results. Organic traffic is the opposite of paid traffic, which defines the visits generated by paid ads. Visitors who are considered organic find your website after using a search engine like Google or Bing, so they are not “referred” by any other website.