You have have seen people talking about the Glass Explorer Edition, or the Explorer Edition of Google Glass. Google refers to people who have paid $1,500 to buy Glass as members of the Explorer program. It is expected that the Explorer Edition of Glass will be improved upon in the coming months or years, with a lower-cost, higher-spec’ed model expected to debut at some future date.
There has been some speculation that the 1-day public sale of Google Glass on April 15, 2014 is designed to act as a “clearance” event. This sale may allow Google to sell off the rest of the Explorer Edition stock, making room in their warehouses for a new, updated version of Glass.