[uriah]

Isn't the relevant "market" searches for whatever keyword group you are considering?

The marketshare of clicks is mainly divided among the 10 sites on the front page. I imagine the benefit, when shared among only 1-9 sites, could be significant. Also consider the benefit of moving from ranking 11 to 10 or from 2 to 1, for example.

Though I can't speak for the efficacy of this technique, this fairly old article suggests submitting competitors articles to directories to reduce their perceived (by search engines) quality: http://www.bluehatseo.com/open-questions-when-to-never-do-ar...