According to Nielson (link to complete article including links showing designs)

... many companies were undertaking significant intranet overhaul projects. Today, the predominant approach to running intranet design projects is to engage one or more consultants and external agencies to contribute parts of the design, while keeping overall control inside the company itself.

This year, 60% of the winners were designed by a combination of in-house and outside resources. The remaining 4 projects were done completely by the company's own staff. None of the winning intranets were designed exclusively by an external agency, even though this was a fairly common approach in earlier years.

If companies take more ownership of their intranets and devote resources to building sufficiently large intranet teams, they gain in-house expertise in the main areas of intranet user experience. Not all companies can afford intranet teams that are big enough to do everything on their own, however. Nielsen advises that there are at least 3 reasons to periodically consult "outsiders" about your intranet:

1. To get a fresh, independent perspective. People who work on the same project for years can become too accustomed to a certain way of doing things.

2. To provide deep expertise or a narrow skillset that the intranet team can't justify adding to their permanent, full-time headcount.

3. To alleviate workload during crunch times, particularly during large redesign projects or rollouts.