The document describes communication methods available in 1979, 1989, 1999, and 2009. In 1979, there were 6 listed communication methods including telephone, letter, telegram, CB radio, morse code, and smoke signals. The number grew to 7 methods in 1989 with the addition of mobile phones, and to 13 methods in 1999 with many internet-based options like email and web conferencing. By 2009, there were over 20 communication methods listed, demonstrating a significant increase over time as technology advanced, especially with new digital and wireless options.