You can look at orders and statistics starting from a particular date by using the filtering on the website. You can set start and end dates (and many other options, including symbols and lot sizes).
Separately, all our publisher apps have an option for setting a start date. All trading activity before this date is then ignored, and is not published to the website at all. For example, there is a IncludeIfOpenedSince parameter in the Publisher EA for MetaTrader 4.
You cannot set a start date if you are using account sync (but you can still use the filtering).