What Factors Influence Search Engine Traffic?

I’m a stats fanatic — I track my Google Analytics stats (among various others) constantly. Ever since starting my blog, I’ve noticed that my search engine traffic has gradually increased over time. Considering that I’ve read about how “content is king” on so many occasions, I started thinking about how the amount of content on my blog relates to the amount of organic traffic I receive. After a bit of time-consuming effort, I found the following trend between the number of blog posts and daily average search engine visitors.


Obviously, there appears to be a direct correlation between the two pieces of data. While it can’t firmly be stated that the amount of content on my blog directly results in a substantial increase in visitors, I think it is a fair assumption that quantity of readily available website content does positively influence the number of search engine visitors received.
Data Gathering Process
The approach I took is not necessarily scientific, but it was about as close as I could get. I started by logging into my Google Analytics account and requesting the number of search engine visitors per day since my blog started. Fortunately, Analytics offers a simplistic means through which I was able to export the data in a CSV file, which I was then able to import into Excel.
I then calculated the number of posts on my blog per day and lined them up in the Excel spreadsheet alongside the number of daily visitors. As a result of some days having the same number of blog posts, I averaged the number of daily visitors per number of blog posts accessible.
Finally, I generated the graph you see above, which demonstrates a rough upward trend when comparing the two pieces of data.