For every Dynamic Parameter Action you provide, we validate it with the content in our system to check if the requested action is content neutral. We look for URLs we know from your site to which the rule applies and check to see if the content retrieved from the rewritten URL (rewritten per the action) is substantially similar to the content of the original URL. There are 2 possible failure conditions:

1. We do not have enough information to do the validation. This can occur if we have few URLs from your site to which the rule applies or if the rewritten URL form was never seen by us before
2. We found enough URLs from your site but found that the original and rewritten URL do not have substantially similar content.

In both these cases, we fail the action since we can not be sure that it will not be harmful to your site's representation in the index.

If the validation succeeds, we go ahead and apply the action to our search engine.