My husband and I own a farm and we rent out some property (cottages) for a little extra income. Recently I received a letter from a guy who stayed on our farm a few years ago. A youngish guy in his 20s. He asked how I was and how things were on our farm, and he also sent a recent pic of himself. We were hardly good friends or anything like that, but we would acknowledge each other with a "hello" if we passed each other on the farm or in the town. Is he making a subtle amorous advance towards me? I don't usually receive letters from past tenants! He also started the letter with my first name, and signed it off with his first name. Isn't using first names a little bit "familiar?" for two people who weren't really friends? I'm not sure if I should mention it to my husband. Should I reply to him?