Yesterday was the 2010 Y! Hadoop Summit. Be sure to read Ryan Rosario's coverage. Many of presentation talks are linked from the Agenda page and via the YDN slideshare channel. I'll highlight a few presentations that caught my attention:
XXL Graph Algorithms - by Sergei Vassilvitskii Connected component analysis in large graphs
Mining Billion-node Graphs: Patterns, Generators and Tools - Jimmy Lin's presentation on experience computing PageRank on a section from the ClueWeb09 web graph.
Hopefully, the morning talks will also be made available online.