Changes to exam format of PMP exam

There are more processes. Contents are more detailed. Some processes names have changes( eg Quality Assurance is nor "Perform Quality Assurance"). Some terms have changed ( eg Earned Value, Planned Value had other names in the old version). A lot of the description is much more detailed.
The new PMBOK also has a chapter describing in detail what all the changes are, so you can see that there if you are interested.

What it may mean to you practically — the new version PMBOK(PM Book of Knowledge) has nearly DOUBLE the pages (400 +) than the older version !!!