Site top 10 for key word for a couple years disappears...

[Webfanatic]

My site that has been top 10 for a couple years now for a certain key word only shows up on the "omitted results" now. Ommited results are the results they consider "duplicate content" so they put a link after the very last search result where you can access it.

The site shows up under other key words no problem, its just for this one key word that im not longer to be found in the top 10 main results. Also, noticed some competitor sites missing as well that were top 10 for a couple years too. The ones these are happening to seem to be sites that have a DMOZ description...that is the only thing I can pick up.

This is occuring at most of the servers. Some servers (not many) still return the previous results with us in the top 10....

What is the story behind this?

The last time this happened it returned the following morning but now its been longer than that....anyone can help me?

[goofy]

There could be a number of reasons that this could happen although without knowing the site etc it is pretty difficult to have some idea where to start. Search engines are always making changes to their ranking algorithms to provide more relevant content so these changes may be affecting your site. First thing I would do is check for duplicate content/urls and check that links on your site aren't broken.