Under the old rules, if an immigrant violated his/her nonimmigrant visa within 30 days of entry, such as obtaining employment or getting married, USCIS will assume the immigrant had misrepresented his/her intent in a flagrant attempt to get out of the longer procedure of becoming a legal resident. If an immigrant married within 60 days of obtaining a nonimmigrant visa, there would be no presumption of misrepresentation. However, it could still create the suspicion of misrepresentation, resulting in further intensive questioning by the USCIS.
The new rule is essentially an extension of the 30 day rule. Previously, it was only fraud if this occurred within 30 days of arrival in the U.S. Now it is considered fraud if it occurs within 90 days of arrival.