The problem about this article is that it describes deferred *shading*. Deferred *lightning* (aka light prepass) is also a technique that allows using many light sources, but it's implementation is often completely different.
The main disadvantage of deferred shading is large memory usage (many G-buffers which often stores not only information required to render lightning but also data needed by some post-processing effects), while deferred lightning needs to render geometry few times (it doesn't depends on the number of light sources, though) what may cause performance hit.
Deferred shading is now quite easy to implement since we already have all post-processing code (Actually, I'm still trying to resist the temptation to start experimenting with it
). Light prepass rendering needs a bit more work. However, it is a complete waste of time to implement it now, since the existing, old FSO code is not ready for such things. What has to be done first is to overhaul current rendering code in a way it will allow using various rendering techniques: multi-pass lightning and either deferred shading or deferred lighting (since, none of these two techniques seems to be much better than the other it may be a good idea to try using both of them before final decision will be made).
(I've also heard about light indexed deferred lightning but I'm not familiar with that technique yet.)
