Reading along, I had to pause and highlight this from the second link, because I thought it was an amusing comment (last sentence here)....
Normal matter -- you, your computer and the air you breathe -- is made of atoms, which are composed of protons, neutrons and electrons. Scientists call this "baryonic" matter. They suspect some dark matter is of the normal, baryonic variety. This might include brown dwarf stars and other objects that are simply too small, or too dim, to be seen from great distances.
But most dark matter is thought to be non-baryonic -- truly strange.
If this is true, then just finding the stuff will be difficult, because researchers don't even know what they are looking for.