I disagree. Because the things I value are different from the things everyone else values in a vacation. Same reason I can look at the bestseller list in Amazon and be completely uninterested in most of the titles.
That's not to say that I have the same taste as all my friends, either. But it's true that their experiences are often much more meaningful, if only because I know them well and understand how they would come to the conclusions they came to regarding a specific review, and I can extract a lot of information from that.
More than that, though, I want Google to be able to learn from my preferences and my friends' preferences in order to point me to the most relevant content.
The collective knowledge of the internet as an aggregate, averaged out, is not useful to me. It doesn't become useful until it's filtered to suit my needs. Which has always been Google's value proposition.
Some of the recommendation engines out there (and it seems everyone has one these days) are really good at figuring out my tastes and preferences. Netflix, Amazon, and hunch.com (now owned by eBay) come to mind. hunch.com recommendations are freaky-good because they ask questions whose core intent is to learn your tastes.
You're right that my friends' tastes are only weakly correlated with my tastes. Assuming my friends and I have the same tastes is an error.
I'd also like to add that the reviews of experts are something I still value over the reviews of others. For example, I'll pay close attention to what Andy Ihnatko has to say about new Apple stuff. Rotten Tomatoes does something interesting in this regard: they keep the expert reviews (e.g. Roger Ebert) separated from the "everyone else" reviews.
If you think about it, a core idea of pagerank was to figure out which sites are most authoritative. Now the question becomes: who is the most authoritative on topic X?
Now the question becomes: who is the most authoritative on topic X?
I think that was Google's project. I think now it's: who is the most authoritative on topic X in a way that's personally relevant to me, even if I have never heard of that person before?
I sort of agree with you on professional reviewers, but I sort of don't. The dilemma of a professional reviewer is that as soon as you're a professional reviewer, you're not really a normal consumer anymore and your experience of a product is going to be very different. (For example, a common complaint about the Android eco-system from reviewers is that it's annoying for each manufacturer's user interface to be slightly different. But a normal consumer who buys a phone and uses it for the length of a contract really doesn't care about this so much as the quality of the skin itself.)
So, basically: I think professional and amateur reviews both have value.
More on topic, though: while I don't really subscribe to the "filter bubble" theory (I still think the digital medium exposes people to way more different perspectives and arguments than pre-digital), I do kind of wonder about the turtles-all-the-way-down aspect of all of this algorithmic ranking. I think it's a subtly different problem.
"Now the question becomes: who is the most authoritative on topic X?"
That question is also answered as part of this launch, as the "People and pages" bullet point. If you're in the fraction of users who this has rolled out to so far, try searching for [jquery]:
That's not to say that I have the same taste as all my friends, either. But it's true that their experiences are often much more meaningful, if only because I know them well and understand how they would come to the conclusions they came to regarding a specific review, and I can extract a lot of information from that.
More than that, though, I want Google to be able to learn from my preferences and my friends' preferences in order to point me to the most relevant content.
The collective knowledge of the internet as an aggregate, averaged out, is not useful to me. It doesn't become useful until it's filtered to suit my needs. Which has always been Google's value proposition.