He meant that he posted it prior to blue_beetle's comment in 2010. I had claimed that blue_beetle was the first person to put it on the internet, and he posted proof that he had posted a similar idea before blue_beetle did.
The reason I remember it is because I posted it as a HN comment, and then a few weeks later someone basically rewrote it into a blog post and got tens of millions of page views and tons of mainstream media coverage. Had that not happened, there's no way I'd remember now.