In addition to the old functionality, you now have the ability to choose a specific value among the known values for a given URL parameter. This is important when a parameter is relevant to the content, but different values of this parameter lead to similar pages. For example, consider a sorting parameter, like "sort-by" in the following URLs:

http://example.com/shop.php?category=candy&sort-by=asc-price&page=1
http://example.com/shop.php?category=candy&sort-by=desc-price&page=1
http://example.com/shop.php?category=candy&sort-by=asc-price&page=2
http://example.com/shop.php?category=candy&sort-by=desc-price&page=2

...To avoid duplicates but still keep our indexing consistent, you can simply select action "Use specific value" for parameter "sort-by" and choose one of the valid values, say "asc-price".

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