I am constantly amazed that people on news.ycombinator.com are surprised that YC companies get lots of votes. There are a lot of people here that are YC fans and are more likely to upvote something if it's about a YC company.
And I'm one of them. I don't just upvote anything about any YC company, but I'm a huge fan of Notifo, Heroku, Dropbox, Posterous, and a bunch more.
I'd be very surprised if the "preferential treatment" that you claim YC companies receive is in code, rather than in the minds of many of the voters.
Also, if you look at any recent thread about Notifo, you'll see some comment along the lines of "Notifo is great ... but it'll be a lot greater when we get an Android client." There's been a lot of people waiting for this.
Pretty sure Notifo is just Chad and Paul, but given Paul's popularity this really isn't that odd. Probably just the result of an innocent, "Hey dude upvote my HN submission will ya" text or two.
