40. A system, comprising one or more processors configured to execute instructions that cause the system to perform a method comprising steps of: receiving, from a second user, a specification of interest in being notified about interactions of a first user with the system; receiving, from the second user, a specification of interest in being notified about interactions of a third user with the system; in response to receiving first text that was input by the first user, performing steps of: adding the first text to first content that is maintained by the system; and based, at least in part, on the specification of interest in being notified about interactions of the first user, causing display of first information in a particular application display of the second user, wherein the first information includes a link that provides access to the first content; in response to receiving second text that was input by the third user, causing display of second information in the particular application display of the second user, based, at least in part, on the specification of interest in being notified about interactions of the third user, wherein the second information includes at least a portion of the second text; wherein the second information is concurrently displayed with the first information in the particular application display of the second user.
41. The system of claim 40 wherein the system includes a wireless PDA, and wherein the step of causing display of the first information in the particular application display of the second user is performed by a client-based program that is not a web browser and that is locally installed on the wireless PDA, wherein the locally installed client-based program is a program that is downloaded to the wireless PDA from an application storage that is remote relative to the wireless PDA, and wherein the application storage is maintained remote from said system.