That zero Return on Investment (ROI) doesn't only occur with SEO. It can also happen with paying for an advertising campaign, hiring a public relations agency to place interviews with media, and sponsoring special events.
The big mistake is not test marketing the tactic. For example, try out different combinations of keywords, embedded in different kinds of content, and posted according to a variety of scheduling. Soon enough it will be obvious what is working, at least at the time. Everything changes.
I re-learned this lesson about test marketing when I brought into my life five-year-old Lee K. As the adoption from the Animal Haven, North Haven, Connecticut was being made final, I got ready for the big day. That was Saturday. I ran out and filled the house with dog toys, rubber and furry.
Yes, a neighbor had warned me to try a few out and see which ones Lee K. took to. No no no. Mommy knew best. Despite my most aggressive efforts to foist the toys on Lee K., he ignores them. His favorite amusement is climbing into the pillow case on the bed, hanging out for a while, then climbing out. Fortunately there are a lot of dogs in this complex I can give the toys to. I can't return them because, in my fit of certitude, I took off of the labels and threw out the receipts.