I am seeing a green mossy looking substance on the vinyl siding, on the north side of my house. I am also seeing this on other houses in the neighborhood and around town this year. I'm not exactly sure what it is....moss, mold, or ??. Do you have any suggestions on what I can use to remove it and how to prevent it from coming back? Thanks!

It is probably algae. You can wash it down with a detergent and bleach solution.