Photo Detective -- Using Collars to Date Photos

I'm getting back into the family's genealogy search and I encountered this blog called Photo Detective which guides you to identifying the dates of photos.

http://blog.familytreemagazine.com/photodetectiveblog/2015/03/23/UsingWomensCollarsToDateOldFamilyPhotos.aspx?et_mid=736617&rid=235537058

I'm looking forward to reading the hints and ideas for dating photos and checking out the other aspects of the Family Tree Magazine for living history ideas.