I didn't even know this was a thing I could sign up for and would have been getting points this whole time for the hundreds I've spent on PSN.
When I saw the option to link, I had the same thoughts. I also wondered whether I'd actually get points for everything I've bought (considering they gave me 1 point for my blu-ray movie purchase, I thought it seemed plausible that I'd get 1 point for each purchase) or at least for purchases from this year but nope, got to start fresh. I wonder how much points you get depending on what you purchase there.