I read that submitting too much directories a day will harm a site...... Because of this search engine page position of a site also get affect. (ex: my site page position is in 1st page 8th position).
Submit 20-30 directories in a day because search engine does not crawl all backlinks in a one day. It will take some time to crawl the backlinks. Submitting site in bulk directories will harm your sites ranking...
Likewise submit articles to websites that actually review them, this will stager the link building. IT WORKS!