I have noticed something as I track my SEO efforts. For several weeks I signed up on a large number of paid directories, and as I did I watched with joy as my site steadily climbed the search rankings for my keywords. Then after about three weeks, suddenly it stopped producing results. I continued submitting to directories, but I didn't move up in the search rankings at all.

Then I tried adding some articles to article directories, and once again I started to climb in the search rankings.

So I was wondering, does google disapprove if you use the same strategy for too long and stop rewarding your efforts if they are too narrow in focus?