Moss is familiar to probably everyone living in the Pacific Northwest. It will crowd out lawn grasses, and it grows best when 3 conditions are met: moist ground, shade and a pH of 6.2.
Any metal will kill moss. For lawn moss, I use ferrous
sulfate with 30% iron; on roofs, I use zinc sulfate monohydrate. Killing the moss reduces its size and its grip on the ground and the grass, so I always recommend having me kill it before pulling it out with my thatcher. Here are examples of pulling dead moss.