Techniques for communicating with a user on a network include receiving
acceleration data that indicates acceleration of a mobile network node
associated with a user of a network. The user is a living user of the
network, such as a human user, or a vehicular user of the network, such
as a satellite, plane, ship, automobile or robot. A communication state
for the user is determined based at least in part on the acceleration
data. The communication state indicates a type of network communication
suitable for communicating with the user. Network communications with the
user are based on the communication state. Among other uses, such
techniques allow a network communicating with a human through a mobile
node carried by the human to infer from stopped or unusual motions when
the human's ability to receive or act on communications is impaired or
otherwise affected.