Report prefiltering in CRM 2011 narrows the scope of a report, return faster results and can lead to more revelant data. Instead of just creating a report parameter, report prefiltering uses the Advanced Find fetch queries. This allows the creation of end user defined queries while still in CRM.
A sample query:
SELECT name, accountnumber
FROM FilteredAccount as CRMAF_Account
For more information click the link below!
Dynamics Blog Link: