For another site I worked on about a half year ago, we wrote unique informative articles and published them on the popular article sites such as ezine etc. The links showed up at first in Google, but after a month or two, all of these listings were no where to be found. Do article directories just give you a short-lived link that Google eventually ignores? I just checked by logging into the article directories and the postings are indeed still up and active.
Sa,e for me. I found article posting to be good to push your serp, but dont rely only on a few submsisions. The key is to be constant, id say, at least an article every month. If your competitors are agressive about link building, you must keep the pace. Plus, do other link building activities, such as directories submissions.