Google originally announced that it would begin accepting registrations for its 2014 I/O developer conference on Tuesday, April 8. But at the last minute, the company decided to push the sign-up period back a week. If you want to go to I/O, you'll need to sign up between April 15 and April 18.
This year, Google changed the registration process from a first-come-first-served model to a lottery model. This shift could be behind the delay. The company announced, "We're still working to make the registration process even easier for you, and it will now be open four days starting next week (opening next Tuesday and closing Friday). After the registration window closes, applicants will randomly be selected, and we'll send ticket purchase confirmation emails shortly thereafter."
Google I/O will take place June 25-26 in San Francisco.