I was away almost all day on Friday participating in an inter-agency drill with the Fire Department. While I was away a ton of comments came in on the post about Jim Rogers recent comments. I'll try to answer/weigh in on some of this stuff.TomK was first up with a quick look at a couple of the different index (made into ETFs) compositions and notes some big differences. He then offers up a reasonable assessment of what seems like poor returns more often than not (probably true) and some of the downsides to owning this space.Regardless of what you think of TomK's comment there needs to be an introspective assessment of why you own commodities or why you want to buy commodities in the first place. My reason ...