What Google has done over the years is thwart some of the scummy SEO practices by penalizing websites that do it; a big part of current-day SEO practices are to make your website conform to web and content standards. Basically, turn it into a decent site.
There's still the black market SEO where people hire spambots to send links, but that's been thwarted / voided by just adding a nofollow to links in user generated content like comments.
There's still the black market SEO where people hire spambots to send links, but that's been thwarted / voided by just adding a nofollow to links in user generated content like comments.