As noted by several posts on the Google+ Glass community page (via SearchEngineLand), Google has begun sending emails to Google Glass owners allowing them to invite a friend to the Explorer program. Google has been distributing Glass on an invite only basis up until now (on top of its #IfIhadglass contests), but this marks the first time it is allowing users to invite others into the beta program. You might remember Google used the same invite-a-friend strategy when Gmail first launched. expand full story