I was a Digg member the first day signups were open. A year later, without causing any trouble or even engaging in a single argument (and not submitting any content), my account was banned and I could not get in touch with anyone to figure out why. The most I got was "you were being offensive", which doesn't tell me what I said that was offensive. I signed up for another account, which was banned a week later without me posting a single comment or submitting anything.

I marked it down to me being on a college campus at the time and my IP might have been flagged (my campus got an IP ban from GameFAQs years earlier), but I never returned to the site. In my opinion, Digg was too involved in admin-moderating their community, which leads to a Google-like "no questions asked" approach.