Processing Bodies & Stress Granules

So I'm reading, this article on various structures in the nucleus where mRNA is stored, remodeled, decayed ...? and I'm thinking that it's incredible that we're still discovering new entities in the cell.

Processing body = place where mRNA is decayed but perhaps also stored. RNAi also seems to take place there.

Stress granule = place where mRNA is stored when the cell faces "stress conditions".

I've seen mRNA go into granules when it's injected into the cytoplasm - so although these bodies, granules ... or what ever you want to call them ... are relatively new discoveries (the paper above is only one in a long series of papers), these structures are readily visible.