Platforms may not be the first solution we go to when it comes to separating a room (we rely on less labor-intense options...like rugs), but they really do a bang-up job when it comes down to it. Not only do they give homes--lofts, especially--some needed interest with the varying levels, but you can also take advantage of possible storage space underneath. But even if you don't have the time to build your own platform, you can save space by installing a ledge for a desk instead of a bulky desk.
This is perfect for people who don't have to store piles of files--but if you do need a cabinet, you can slide one underneath, customizing how much storage space you actually need.
Another great example of a custom desk ledge is from my dear friends Monika and Loren: They created their shared home office area in the mezzanine of their Oakland loft by adding a ledge underneath the existing one, creating a split-level desk. They divided the work stations by stowing the computer towers, a scanner, and even a small storage locker in between their respective areas.

If you haven't seen the rest of Monika and Loren's house tour, go check it out here.
(Top Image: Hus and Hem)

Shaw's Original Fir...
This mezzanine area is so perfectly designed for the space around it. Nearly all of the office is out of view from below yet provides a sense of openness to the office dwellers. I'd get warm and dozy up there, hope they have good ventilation!
Not quite sure how the first picture maximizes work area. I mean, it's just a desk lifted up on a platform. You'd have the same amount of work area if you just left that on the ground, minus the fear of accidentally rolling yourself down those stairs.
It's not like it's a lofted area above a living area with desks.
I kind of fear for those monitors in the second picture. I know it's probably not likely that they'd get knocked over, but if they did the fall would kill them!
The office chair in that first picture is pretty nifty...anyone recognize it?