internet - Where is my traffic coming from?

Every now and then, especially when something special has happened, I go and check the statistics of this weblog to see if there is any change. To my surprise, there is very little change in the number of visitors. About 1,800 people have subscribed to my RSS-feed, so that would not have an effect on the statistics, unless they really click through.
But the number of visitors is otherwise remarkable stable. In a few months time the number of daily visitors went to around 1,300, up from 1,200, but otherwise nothing seems to be able to change the numbers substantially. A broken cable, days not not posting by me, a lot of postings: visitors keep on coming.
The number of referrals by other weblogs, while highly appreciated, is pretty low. Highest scorer over the whole of January was Shanghaiist with 63 referrals on a total of over 37,000 visitors.
I estimate its the search engine who bring most of those visitors to me, but I'm not sure about it.