What brings traffic? Word of mouth! if they like what they see, they will stay and promote.
Basically anything that you feel confident to speak about regularly, with something new/interesting every time...An original content, with one strong theme and little variations around this theme, updated regularly, with a consistent quality of writing/shooting/other, and a reactive/entertaining feedback to comments and visitors.
Getting few writers together may also be a good thing to get variety over a same topic, like http://indiegames.com/index.html
(word of mouth, you see ^^)