Okay... so, I finally made up my mind to get one of these. Initially, the whole "wait to be invited" thing was a major turn off because when I saw the website, I wanted to jump right into "pinning". However, I eventually accepted having to wait and somewhat excited to be the confirmation sitting in my inbox (I had forgotten that I had even signed up for it in the first place).
Now, though, I must say that the wait wasn't so bad. I absolutely love the pinning experience and seeing what people around the world have to share with others is inspiring. Here's my profile there: /kinalillet