This year, developers should be able to access videos for WWDC while the event is still underway, language on Apple's website
suggests. The company writes that it will be posting videos for all of its sessions "during the conference" for registered Apple developers. How developers will be able to access the clips isn't mentioned.
Apple's traditional approach to WWDC has been to post videos weeks after the conference is over. While this increases the incentive to attend, it may put some developers out of the loop, in turn affecting development cycles. Apple may want to ensure that app makers are fully prepared for OS X 10.9 and iOS 7, both of which will be revealed at WWDC.