Great design, content is interesting straight to the point and laid out nicely. Eg your article on contextual ad alternatives...
Nothing really to fault at all with your site, however if I was going to be picky the loading time was a bit slow.
Also you might want to make the free ad space a link to your advertising page and I would remove the visitor counter on the bottom as it looks a bit unprofessional.
Apart from that the site is really good