Great conference! Here are the slides and the sessions.
The keynote by Charity Majors was definitely the best one on the whole conference.
I attended the following sessions which I thought to be very helpful:
Online shop reference architecture based on MongoDB database
The complete source code is going to be open-sourced.
Storing time series data in MongoDB for Analytics
The complete source code is going to be open-sourced, too.
A simple node.js/mongoose/elasticsearch application at LinkedIn
Running MongoDB at scale at parse.com