Everyone has his or her own definition of what is considered spam. I think it starts with the “From” line and then the “Subject” line. If I know who the sender is I’ll read it. If I don’t know who the sender is, but the subject line intrigues me I’ll read it. Since we don’t know how someone will react to a particular email, all we can do is manage the likelihood of it being seen as spam by deciding to follow (or not) email best practices.