Possible Cause: If search results include duplicate titles or descriptions, your description fields (description, summary, or abstract) might include boilerplate information.
Action: The more accurate your META tag description fields are, the better your search results will be. Where possible, consider adding descriptions to your document's META tags.
Possible Cause: It could also be that you have indexed the same document more than once, or several links throughout your Web site might point to the same document but do so using different character cases each time.
Action: To solve the latter problem, try using the URLs Are Case Sensitive option to direct Web Search to turn off case-sensitive crawling. Also, remove any duplicate backup files you might have and exclude any backup directories from your index definition.