What-are-the-big-problems-being-faced-in-developing-Google-Glass?

What are the big problems being faced in developing <a href="http://glass-apps.org/google-glass" title="Google Glass">Google Glasses</a>? <br/> http://www.quora.com/Google-Glass-4/What-are-the-big-problems-being-faced-in-developing-Google-Glass