This is a great piece of work for references, lots of info on this, Answer sites have become less and less popular, but the you can really build your name on these sites such as forums, if you are consistent in answering questions frequently. Out of the points you have mentioned, I relay enjoy the "Guest Blogging" point, as this is a win win situation, not just putting out content on other websites, but also welcoming guest on my own site, giving readers a change and a different style of article, as everyone is unique in their own way. I'm actually posting an interview tomorrow with a well known name in the guest blogging. Whichever point one choices from above, consistency is the key, there is no point doing it once, but it should be done on frequently, and over time with patience you will start to see the rewards.
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.