As anuj.pathania said..to promote it offline....i think that the best way to promote online anything is making it popular online and can be a little effort offline also....but since online is what the thing is about...it shoul be better to online promotion.
Try to visit some networking sites on blogs were bloggers meet and discuss your blog there .....and since your blog has competition stuff...you need to hold on.Its better that you get slow response so that it stays on.
