Even if you don't use Twitter or Facebook, it is extremely important to make your blog shareable if you wish to generate more traffic. Don't make your readers work more than they have to in order to share your blog with their friends.
This type of word of mouth advertising is one of the most effective methods of spreading your blog around. Again, we go back to how you would react to things. Are you more likely to click on an ad link or a link your friend shared with you?