Spam more about intent of technique and the extent a technique is used, rather than being a specific technique. Where is the fine line? Varies by industry. Is a user comfortable with the user experience of a site (excessive links, nonsensical text, etc.). Search engines can’t discose where the line is.
Todd Mintz knows PPC…knows Social Media…knows SEO…knows Blogging…knows Domaining…and knows them all real well. He runs growth marketing for )and is also a Director & Founding Member of SEMpdx: Portland, Oregon’s Search Engine Marketing Association, and he can be found here on Twitter and Facebook.