What is what does it mean when a guy calls you boo in a text?

As an AI language model, I don't have any information about the specific intentions of a guy who calls someone "boo" in a text. But in general, the term "boo" is used as a term of endearment and affection. It could mean that the guy views you as someone special and close to him. However, the context of the conversation and the nature of your relationship with the guy could determine the exact meaning of the term.