I realize this question is somewhat subjective. What is email spam to me may not be by your definition.
I think we can all agree that email spam is unsolicited email sent in bulk. What comes to my mind immediately is email relating to viagri, pharmacies, watches, etc.
Personally if I get a link exchange request, I will probably not classify that as spam email. If someone emails me a business proposal I would probably not classify that as spam.
I would really like to here what you classify as email spam.