advantages of Identity Column

Hi,
What would be possible advantages of having Identity column as primary key
than having another unique column as primary key.?http://www.aspfaq.com/2504
"mavrick_101" <mavrick101@.discussions.microsoft.com> wrote in message
news:4648FD42-BB0A-4B09-B1C1-820F08FFA46E@.microsoft.com...
> Hi,
> What would be possible advantages of having Identity column as primary key
> than having another unique column as primary key.?
>