I'm just wondering, why does some accounts only have 1 reputation?
That is, what causes you to be temporarily suspended? I've looked at the "A day in the penalty box" blog post, but I don't really understand.
Moderators put accounts in the 'penalty box' when a user is not responding to requests to improve their behaviour or when they have been caught cheating the system. That way the rest of the community can continue to provide great questions and answers without having to deal with someone who is causing others distress.
You are expected to think about your behaviour for a while, and hopefully when the suspension ends your behaviour will have improved.
An account that has been put in this penalty box will have a notice posted on it giving a general reason for the suspension; there is no need to hang out the dirty laundry, the exact reasons are private and only moderators and the affected account need to know.
There are a few things you can infer from that notice though:
Because invariably the problems with such account involve a lack of trust or are caused by a fixation with reputation, suspended accounts have their reputation set to 1. The owner thus will no longer have to worry about reputation changes, and the community sees the breach of trust reflected in the reputation score on all posts by that user.