Iodine, like many nutrients, works in conjunction with others. When you add Iodine its important you add in all the other required supplements. Those that do have no issues and make significant progress, those that dont have issues.
Mercola, like most docs, simply reads some poorly contrived study and takes it as gospel. Dont just start taking iodine. Stick around, do some research and when you are ready with all the supporting nutrients take the plunge.
Im rather new to Iodine myself but a long time proponent in supplementation as a whole. Ive been taking 50mg iadoral daily for over 90 days now with only minor detox issues and a whole lot of fat loss.