Submitting to directories can't hurt your rankings. Otherwise your competitor will submit your site to 1000 crappy directories and beat you in search engines results. There is no such thing as bad link, bad link=no link. But if you submit to quality dirs, it will raise your rank after some time. Of course, you do not know which directory is good or bad, so submit to as many dirs, as you can and this will give you good results. http://www.submit-add-url.com