The so-called "seal of confession" has not always existed in Christianity. In the earlier days, when members committed more serious sins and wanted to return to the church they had to make a public confession, go through penances in the church, then receive absolution from the bishop.
In the medieval ages, lists were made up for penances. So if you committ X sin you had to do X days of fasting on bread and water, this practice was started in the west and later developed in the whole indulgences thing (so you say a prayer and it had 100 days as an indulgence, so that prayer was equal to 100 days of penance). Of course, this completely negated the ascetic struggle and the Orthodox rightly say.