I occasionally feed some blended in the hopes that maybe my SPS use it as some kind of zooplankton substitute. It's very subjective whether I really see any results, though.
If it's not blended then the particle size is too large for anything to make effective use of it. It's not always practical to blend fish food, though, and it sure does make for a stinky blender if you blend it in tank water. I blend mine for a minute on high. If memory serves, according to Marine Fish Annual 2002 you need to blend it for something like two minutes if you hope to use it as a phytoplankton substitute, but as I recall the growth curve using ESV's as phyto paled badly in comparison to DT's. So probably not worthwhile as a phyto feed. Unfortunately there was no data as far as zooplankton substitute so all I'm really left with is "do my SPS look better because I feed this stuff?" I honestly don't know if I'm doing any good. I "think" so but as you can see it's a hugely subjective/debatable point. I don't seem to be doing any harm so I'll continue to use up my bottle, but I don't know if I'll run out and get a new bottle when this is done.
Sorry I couldn't be better help. If nothing else here's a starting point, and I'm jumping on the thread to see what other people have to say too.
cheers