I've explained it like this: To get on the list, something has to be considered at-least-good by a lot of people, and this tends to reward (1) herd mentality; (2) lowest-common-denominator. The list selects against anything in any niche, even when it's excellent.
As I look back through music that has meant a lot to me, there is just not much overlap with best-of lists.
Note: I'm talking about critics-vote, pooled, best-of lists. Single-critic best-of lists don't average out niche tastes and, for the right critic-listener match, can be very helpful indeed.
Neutral Milk Hotel's "In the Aeroplane Over the Sea", for example, is an extremely polarizing album. Between Mangum's nasally vocals, beginner-to-intermediate technical talent, the inclusion of saws and theramin as instruments; it all adds up to a love/hate affair. I'm not a big fan of any of Mangum's other works, but AOtS has an allure that is just... indescribably gripping.
I don't go around recommending it, but when it comes up in my playlist, I find that I am simply compelled to stop what I'm doing and listen to the entire album, which is thankfully short, as far as albums go.
1. "Tapping into the zeitgeist and participate proactively is great." As you put it so eloquently :)
2. The alternative is to follow your own curiosity and read whatever you really have a hunger for.
Time is so limited it can get hard to choose reading material sometimes.
They also display a bespoke meaning for the stars (i.e. 3 doesn't mean average), so for those that follow that meaning, their ratings will be different.
http://www.thenewdorkreviewofbooks.com/2011/06/amazon-vs-b-v...
Why did Amazon purchase Goodreads?
I read 74 books so far this year. Most of them were purchased from Amazon.
Also, Goodreads has an active review community, and good "by reader" data for recommendations (as opposed to Amazon's "by account" data. If Amazon were smart, they'd be working very hard on improving recommendations with their Goodreads data.