Originally designed for classroom or open access environments in Schools in the UK, where any one of hundreds of students could potentially log on to any PC and would expect to be able to access their email; the roving client utility is now in use on thousands of workstations world-wide.

However, the effectiveness of this utility is not limited to educational establishments, it could well save a lot of time and trouble in any environment where more than one user has access to a given workstation.

By default, Outlook does not easily fit into a multiple user profile environment, adding Microsoft Exchange Server into the mix complicates matters further:

• In it's default configuration Outlook stores all its user profile information locally in the registry.  Each user must have an Outlook profile configured on the PC they intend to use before Outlook will successfully start.
   
• If the Outlook profile is to include the client for Exchange Server, the user's mailbox details have to be pre-set in the profile as well.

The net result is that if you want to use Outlook in a roving profile environment you either manually create a profile for every user on every machine or you get something like Outlook Client to do it for you on the fly!

Microsoft have made tools available to extend Outlook's support for roaming profiles, a search of Microsoft's knowledgebase (http://www.microsoft.com/support) for 'ProfGen', 'NewProf' or 'ModProf' should give you all the information you need. 

However, these tools have limitations that make them inflexible or difficult to use for many people due to the scripting or batch file requirements.  The Outlook Client utility will usually resolve the problem in a flexible and easy to implement manner.