COD ships with the ability for "crowd-sourced" rating of sessions. The idea is to the the wider community have a say in DrupalCon session selection. I think this is a wonderful goal.
The practical reality, however, is this:
a) There are some 350 proposed sessions for DrupalCon London. Let's be generous and say that it's only going to take me one minute each to read the session description and presenter list, consider what score I'd like to allocate to that session, and cast it. I would need to find nearly 6 hours of time in order to give each session its proper consideration.
b) As a result, I'm totally not going to be able do that. Instead, what I'm going to end up doing is hunting around the list for people I know give good talks, and rating all of their things up, without really reading the session descriptions overly carefully other than the titles, because I'm pretty confident they'll do a good job. This turns DrupalCon into an insider's club that is unfairly biasing my votes against newcomers in the community who might have a lot of really cool, insightful things to say.
c) Further, people with louder voices in the community, such as a large, well-known Drupal company or people with several thousand Twitter followers, are going to have a much easier time peddling for votes than smaller shops and independents/freelancers. This turns voting into a popularity contest, not anything remotely resembling a merit-based selection of sessions. There are a lot of brilliant people in our community who don't have 25+ employees, who don't have 500+ Twitter subscribers, and who don't have a mailing list. This shouldn't affect their perspectives brought into DrupalCon.
As a result, the DrupalCon session presenter list tends to look pretty stale, with the same old same old people in it all the time. There's a big perception of unfairness among the "little guys" who are not as well-known or don't have as big of a "base" from with which to draw votes. And, because of these factors, some track chairs ignore the results of voting altogether, making it a colossal waste of time for all involved.
So I would love to open up a discussion on how we take what we want to do (give the community a voice in DrupalCon session selection) and merge it with the practicalities that such popular voting entails.