A handwritten or handdrawing messaging system employs a handwriting messaging component operable with a messaging client of a mobile device connected to the data transmission network to set up a handwriting data capture area in the messaging client into which the user can enter handwritten or handdrawn input through a suitable manual input device, and then operates to capture the handwritten or handdrawn input and send it as a handwritten electronic message to the intended recipient. It also sets up a graphical data viewing area within the messaging client for viewing handwritten electronic messages sent to the user. Preferably, it is a small-footprint software module installed with the messaging client of the mobile device. The mobile device can be any type of wired or wirelessly-connected portable device operating on a computing platform, such as a personal digital assistant (PDA) device, game console or player device, or other mobile messaging device. The manual input device can be a touch-sensitive screen, tablet with pen input, stylus pad with stylus input, or an attached drawing pad. The system is particularly useful for messaging via mobile game player devices, so that people all over the world can send handwritten messages, chat, and play handdrawn games with each other.