Google announced in the official Adsense blog that they have made changes to their initial review process. Their two step review will include the original one that take place after the new publisher applicant fills out the application form on the AdSense site. If the site passes, publisher applicants get access to their account where they can create ad code to be placed in their site. This is where second step review will take place.

Read more in detail on Google:
Inside Adsense Blog.