User blog comment:Dopp/Technical Update: February 7, 2012/@comment-957747-20120212023454

"We're updating the default style for new tables created from Visual Mode for a more attractive look and feel. This will not affect any existing tables, and it will not impact editors who work in source mode. These new defaults (class="WikiaTable") can be easily changed in source mode or overridden with custom CSS. "

This statement is incorrect. It is actually  that is added to tables created with the table button in visual mode.