They still work. However, if you trip a filter, your site is going to get dinged because Google now penalizes for certain types of link building, regardless of whether your intent is good or not. They also penalize for what once was considered "ok".
Basically, just go out and spend money on Adwords, then Google will love your website! You'll get all sorts of traffic from Google and your business will thrive! (provided that you keep spending money on Google Adwords)