One supposed expert in SEO persuaded a considerable number of US real estate owners to add his link system to their sites.

This consisted of link pages categorised by State.

As he found each new potential link, he added it to each of his client sites, thereby creating identical pages.

When we last checked, not a single one of these pages was recognised by Google.

We have also come across directory owners who do exactly the same thing, using multiple directories.

What a complete waste of time.