http://secondlife.com/vote/index.php?get_id=1617
The idea is to basically have ditinct depth of field (which determines how far you can see) for landscape and objects. The purpose of this is to have the possibility to view distant landscape and breathtaking panoramas instead of the current foggy/sandbox view you actually get without affecting the bandwidth too much. Due to the fact that landscape doesn't sport customized textures and it's probably handled in a very different fashion than current user created objects, that would mean it should be quite fps and bandwidth friendly. Tired of owning a house on the lake and not being able to see the other shore? You just created your own majestic tower and all you can see is fog? I believe this prop is for you. Of course if you dislike the system, you can always set the object and the landscape DOF to the same value.
The prop also suggest to have darker shadows during day and night: The current shadowing system is so subtle it's barely visible. I'm not talking about casted shadows or self raytraced shadows (I know that would need a complete reconstruction of the engine) but the very simple shadowing we get on the surfaces. My suggestion is to reduce ambient light a bit, and even link the ambient light directly to the time of the day, so that we can finally have more realistic mornings, sunsets and blue nights.