Hi. Very nice to see you here Matt. Logically, what is the difference between paying for links and spamming sites, or, spamming webmasters, or other active link building practices?

Also, I wanted to ask, what is the difference between advertising on a website by the way of them putting my link on their site, somewhat like the google link ads I suppose, but on a more permanent basis, that is, at what point does direct link advertising for exposure to the traffic of that certain website become link buying?

Should google not try and rely on other variables which are more reliable determinants of quality than links?