You'll be tempted with the comments and some regular traffic from dofollow directory, but when you set out to monetize, have you thought what it affects?

if you search you will find tones of DoFollow blogs, but is it’s not on the niche you are looking for! And also maybe they changed their strategy and Google still cashing them as DoFollow, but in fact they are not anymore! So.. forget about DoFollow blog lists now! and check this out!