I found this article rather interesting and a different look at what I've been told over the years. Unlike many people I actually have washed my seasoned pans in soap and water and had nothing at all happen to them. Still well seasoned and cooking like champs. Myths are made for busting, I guess.
The Truth About Cast Iron Pans: 7 Myths That Need To Go Away | Serious Eats
The Truth About Cast Iron Pans: 7 Myths That Need To Go Away | Serious Eats