^^ this.Yes they do work, but as part of other efforts.
^^ this.
Just search the forum for case studies. I know I did a couple the past year.
Search online and you will also find case studies.
The past few months I worked on a couple local websites and some niche website. They all got movement after placing links on tumblrs.Well, times do change) I may have been working last year but not now or it has lesser impact on improving rankings.
But I got you.