I took some time last week to work on a feature Vince requested. We've been using a sort of hacky mesh decal method to get shadows on semi-transparent surfaces, which is something Unity doesn't support out-of-the-box. The problem is we could only make it work efficiently for direct light shadows - like sun/moon - and Vince wanted to be able to use decals on dark underground tunnels, where mostly only spot (flashlight) and point (torch) lights are visible.
Decals are very important for detail. They allow us to add those small details that make environments truly unique. So I went ahead and implemented a simple deferred mesh decal system, where decals are rendered just like any other opaque deferred surface, therefore becoming fully integrated with Unity's deferred pipeline, correctly receiving light, shadows and post-processing.
Not only do we get shadows now, we also get occlusion and other effects used to add depth and realism to our scenes. They're faster too, so we can use more of them. Here are some examples showing how they finally feel connected to the environment: