I've been reading HN for years, and often don't pay much attention to who has written or posted the articles. I just scan down, click on whatever catches my attention, and read.
I'd hesitate to say that social factors never come into play, but generally I don't think I pre-judge material based on the credentials of the author. If an author makes a good point, then I will recognise that, whether it's a celebrated blogger or somebody I've never heard of.
My own, rather limited, blogging experience backs this up. I've had a number of my own blog posts rank highly on HN and Reddit, but I don't doubt that 99% of the people who read and up-voted them had never heard of me.
A couple of things which could have affected it:
* the title was much snappier 2nd time around
* sometimes just simple timing/luck plays a big part, e.g. getting those 4-5 early votes which gets an article on the front page