While you can log into the same account on multiple computers this is typically not a good idea. I usually disable this ability for everyone other than for the server administrator accounts. If you're wanting to keep files and data in sync the simplest thing to do is to…
1) Use file sharing for standard files so that they're on the server and hence, only the one copy for each person to access
2) While group addressbooks can be used with the addressbook server it's not implemented directly in Lion/Mt Lion Server so the simpler way to do it is to have an "extra" account to share services like the AddressBook. They can either use this account as their main addressbook or as an addition to their addressbooks that are specific to their accounts.
Thank you, 'Infinite Vortex' (great name!), that's helped alot.
Thats clarified how to go about setting up the accounts - the file sharing on the server for common files is a really good way round it. I am a newby to Macs (although I have had unix workstation experience years ago). If I want to file share across a network does the 'Mac with the files on' have to be running the server version of the Lion operating system in order to get the export/sharing functionality?
BTW I was playing around with address book and icloud and I discovered that if you have two mac user accounts linked to the same 'icloud' account then you get the same address book on each account.
If I want to file share across a network does the 'Mac with the files on' have to be running the server version of the Lion operating system in order to get the export/sharing functionality?
To be totally honest with you, any Mac can provide file sharing functionality. The difference between the doing it from a client or server version comes down to the way that it's managed and controlled rather than the file sharing itself. Either way though, the answer is yes, you do require the files/folder you wish to share directly available on a local volume to the computer doing the sharing.
What you probably need to consider is what level of services you want to offer office staff and in turn, what level of management complexity you want to go along with that. If all you're after is shared files and a shared addressbook/calendar you can simply achieve that with OS X client with iCloud and without needing OS X Server.
Even though Apple sells OS X Server as a "server for everyone" it still requires an above average control of OS X plus a base knowledge of its underlying technologies. That's hardly "everyone". That said, OS X Server does provide a level of control and functionality that can't be matched though the client version controls and/or iCloud.
The methodologies that come with OS X Server aren't always better than client version implementations, just sometimes different. There are benefits to both.