That article was basically talking about the principle of least privelge. As far as how important it is this is something i read Microsoft is adding in Longhorn:
[ QUOTE ]
What are the key hurdles between now and the final launch, and what aspects are the most challenging?
Allchin: There are several changes that we are going to make that are going to take a lot of focused testing. They are things that customers have really wanted, but they are complex. (One of these is a feature internally known as LUA--Least User Access.) It's basically running users (in standard-user mode), not in (administrator mode, which makes it easy to add new programs and make other changes, but also to allow major changes to be made by malicious software).
If you are running as a standard user, then we have a lot to do in terms of application compatibility and also getting the user experience right so that users aren't surprised. That's a hurdle. We have most of the work done, frankly, but we expect there is going to be a time frame to hone it.
[/ QUOTE ]
From:
http://news.zdnet.com/2100-9590_22-5807061.html
LUA is basically Microsofts implimentation of the principle of least privilege from a user perspective in Windows. Google "least privilege" if you are interested in reading up on the subject.