I have a friend that is an explorer, and he invited me to the explorer program! I'm pretty stoked for the chance to play with them and start looking into making a few applications. When will the invites actually start rolling out so that I can put in an order? I do a search for 'google glass invite' everyday waiting for someone to say that invites are starting to be delivered.
As most have mentioned, the earbud makes them stand out a little more than I would like. They're already going to be obvious without a large bud in my ear. I'm happy that Google didn't take away the bone conduction due to complaints, but rather gave another option to the user. The earbud will be nice in a rather noisy environment, but will obstruct my hearing in that ear somewhat unlike the bone conduction. I'm guessing this is a somewhat temporary fix so that they may upgrade the bone conduction hardware for better quality on the mass production unit.
As for the target market for this kind of accessory, that's what the explorer program is all about. I'm sure Google has no idea who will actually want to throw a rather large pair of 'glasses' on their face, and walk around talking to themselves. Privacy is somewhat a concern, especially with the NSA/PRISM squabble that's been on peoples minds, and also the chance that some creepy person may be taking pictures or videoing you without your knowledge. To the people concerned with the NSA/PRISM issue, who cares if you have nothing to hide? Sure, there might be some weird guy (the guy monitoring the video feeds in SouthPark S16E01 'Reverse Cowgirl' comes to mind) monitoring what everyone is doing, but as long as you're a law abiding citizen, not doing anything stupid, you have nothing to worry about. The only way of fixing the picture/video issue would be to make some sort of shutter to hide the camera from view when not in use. If there were to be a light that would turn on (like on some laptops) when in use, it would look rather silly in my opinion.
All in all, I'm excited to see where this technology goes. Everything will be wearable at some point, this is just part of the first steps to bettering this kind of hardware for normal and everyday use. I feel like the smart watches will have more of an appeal to most everyone starting out, but I'm excited because all I can think about is Dragonball Z and the Scouter that the Saiyans wore. :-D