[Stuart]

In many organisations vacancies are advertised internally first. It's a way of encouraging career progression for existing staff. If HR are doing their job correctly there is no element of nepotism as the line management of the post are not the only people in the process.

Ultimately you then end up with a vacancy, which is advertised externally, unless you are looking to reduce overall numbers.

High profile positions can be advertised internally and externally at the same time. The sift for interview is 'blind' so you wouldn't know who fell into which category.