There are a number of rule changes that have been introduced for 2012.
Quick summary:
Rule XIV: All entries must be sent WITHIN FIVE (5) DAYS after the end of the contest.
Rule III.13: Post-contest correcting of call signs by using any database, recordings or confirming QSOs is not allowed.
Rule XII.2: All sent and received exchanges are to be logged. In addition to the number exchange, the call sign sent by an entrant during a completed exchange, must be logged as sent by the entrant. All QSO exchanges must be logged upon QSO completion.
Rule XIII.3: Unsportsmanlike conduct can be grounds for action by the CQ WW CC. Examples of unsportsmanlike conduct includes but are not limited to…..post-contest modification of a log by using data sources to correct call sign/exchange errors
Rule III.2 – You must not exceed the total output power limitation of your chosen category on any band. Total output power on any band at any time is measured at the output of the active amplifier(s).
Rule III.14 – All competitors are expected to have read and to comply with the rules of the chosen category. The entrant agrees that any violation of CQ WW contest rules makes the entrant subject to either a red or yellow card (see rule XIII).
Rule XII.2 – …All QSO exchanges must be logged upon QSO completion.
An explanation of the changes can be seen at http://www.cqww.com/rules_2012changes.htm
View the complete rules at http://www.cqww.com/rules.htm