Microsoft updates this week will contain code to check for pirated versions of Office XP, Office 2003 and Office 2007. It’s the next phase of the “Office Genuine Advantage” (OGA) program which will throw up a nag screen that says “This copy of Microsoft Office is not genuine” if it finds a pirated version.
Theft by software pirates is vast. It was estimated that 41 percent of the software on machines throughout the world in 2008 was pirated – a $50 billion loss to manufacturers and resellers.
Link - Sunbelt Blog: Microsoft rolls out next phase of Office Genuine Advantage