Static forces in spider webs are discussed in terms of the changes they produce in the position and shape of the web filaments. Material properties of the silks are related to the structure and functions of the spider webs. Gravity and wind forces are considered, but localized forces are particularly interesting. They may be used to measure by simple optical methods the forces and energies involved in different routine operations and emergencies. Rapid disturbances of the filaments create two kinds of signals which circulate separately through the web. Their speeds are given and their time development describes the nature and location of the disturbing source.