It's my understanding that the system for Hold 'em is that the button travels around the table to the next person to the left of the last person who had the deal.
The person to the dealer's left then puts in the SB and the person the the SB's left puts in the BB.
Now, I don't know if there's some finesse to this rule that I haven't heard; but on Everest Poker, at least at their free, limit tables the button frequently jumps to an empty chair or the SB is hopped over.
For instance twice this morning I was in a position where I was the BB and there was no SB.
This is a bug right? This is against the rules?