In the early days a comment came with a footer with links to the authors little homepage, FOSS project or startup business. Killing this also killed organic linking. This idea that all self promotion is evil was the greatest mistake. That Google went along with it and even promoted nofollow puzzled me greatly.
I haven't put any effort in writing long well-researched comments since that time. I wouldn't dare put more than 2 references in a comment here. 4 would be pushing it.
As if nothing interesting was written before about anything?