The application states that Google is "expanding The Explorer Program little by little, and experimenting with different ways of bringing new Explorers into the program." The web page, which you will find by clicking on the sourcelink, previously offered the latest Google Glass news to those filling out the online application. Now, the stakes are much higher.
There is one important restriction. Those applying to be added to the Explorer program must be a U.S. resident. If you qualify and would like the chance to become a Glass user, fill out the online invite and hope for the best.