great john!! i am sure your articles would be qualitative and original the search engine loves the fresh content i also get the organic traffic by writing the unique articles and couple of them are on 1st page without link building
the explanation is this: google, yahoo, bing or other search engine has increased your position for a specific keyword or for different keywords and as a consequence you traffic became greater. Insert analytics on your website and you will know the source of that increased traffic.
Hey its a great news then why you affaired for this every one wants that his blog or website hitting is increase rapidly then why are you worried keep posting in your blog or website.