This guy is most likely affiliated with either Sony or a 2nd party. At worst a 3rd party with very close ties to Sony. So he's either a viral marketer or could just be a young fan boy working at some game company somewhere (yes, many game developers/testers/designers are fan boys, unfortunately it seems to be human nature to take sides).
Sony is notorious for using viral marketing tactics in Japan, they have legendary amounts of it and it's going on to today on 2ch.net. They haven't really been caught doing it in the US, but it's pretty obvious on a forum like GAF who is there for the sole purpose of praising anything Sony. There's a big difference between developers who happen to be supportive of Microsoft and someone who is being told what to say and when to say it. The former is simply a fan, the latter is a viral marketer...
I think Microsoft is being pretty clear in using things like gamerscoreblog instead of resorting to dirty tactics like this.
I am 100% sure that this guy is pulling at least some of this from company line, too many things are verbatim from what Sony is telling various developers. You are right that he is also injecting personal opinion.
What's funny is that people aren't catching on to a couple subtle warnings: launch games are going to be slim pickings, and diverting attention to PSP stuff also points to hardware shortages. Sony's strategy is clear: If you buy a PS3, you're lucky, but if you can't buy it, then why not buy a PSP instead? You are loyal to the Sony brand, right?
Even Spong is catching on to this news, Sony is running out of time to cover this one up:
http://news.spong.com/article/10687
TGS will prove interesting, they will drop many bombs I'm sure, but behind the smoke and mirrors that Sony is so good at, I don't think there is going to be much to play in 2006 on PS3. They're at least a month behind where they need to be right now, maybe two. It's almost freaking September, and they haven't even started making the darn things.