any update ....
you could try to use the Body.Text property to match it against words you would like to block. You should use a criteria that only triggers your rule on objects which contain text, such as text/html. The problem here is that parsing the complete body of an object requires a lot of resources, so it will most likely have an impact on performance. Also filtering on single words may cause a high number of false positives, e.g. looking for "sex" will also cause a site containing "msexchange" to be blocked.
thanks asaban , u really helped