Welcome to the Porcelain Insulator Collector's World of Mud

From the overview site:

Glass insulators were first produced in the 1850's for use with telegraph lines. As technology developed insulators were needed for telephone lines, electric power lines, and other applications. In the mid 1960's a few people began collecting these antique glass insulators. Today there are over 3,000 insulator collectors. Insulator clubs, local and national shows, and good reference books are available. Auctions of Vintage Insulators are available too.