That's your computer (or the software that powers this site) trying to interpret unicode as ASCII. The original was either in a non-Roman alphabet (like Chinese) or a Roman alphabet with lots of diacritical marks (like Vietnamese.) It's just spam, pure and simple.
Another fly fishing forum which I follow (and which recognizes unicode) gets a lot of spam in Vietnamese. It's always trying to sell cinnamon as health food. Nothing particularly sinister, just useless.