There is disclosed a system for maintaining content lists. The system includes nodes interconnected by at least one data network. The nodes are organized hierarchically to comprise a root node and at least two child nodes. The root node stores a list of content items expected to be of interest to a particular user; transmits data reflective of an update for a subset of the list to at least one of the child nodes, the subset selected based on at least a predicted future location of the particular user and a geographic location of that child node; and receives data reflective of an update for the subset of the list from at least one of the child nodes. The at least one of the child nodes stores the subset of the list; determines an update for the subset of the list; and transmits data reflective of the update to the root node.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. A system for maintaining content lists, the system comprising: a plurality of nodes interconnected by at least one data network; the plurality of nodes organized hierarchically to comprise a root node and at least two child nodes; the root node configured to: store a list of content items expected to be of interest to a particular user; transmit data reflective of an update for a subset of the list of content items to at least one of the child nodes, the subset selected based on at least a predicted future location of the particular user and a geographic location of that child node; and receive data reflective of an update for the subset of the list of content items from the at least one of the child nodes; the at least one of the child nodes configured to: store the subset of the list of content items; determine an update for the subset of the list of content items; and transmit data reflective of the update to the root node. 2. The system of claim 1, wherein the root node is configured to transmit an update for the list of content items to a device operated by the particular user. 3. The system of claim 1, wherein the root node is configured to receive an update for the list of content items from a device operated by the particular user. 4. The system of claim 1, wherein the at least one of the child nodes is configured to transmit an update for the subset of the list of content items to a device operated by the particular user. 5. The system of claim 1, wherein the list of content items comprises a location of at least one of the content items. 6. The system of claim 5, wherein the list of content items comprises an indicator of network transmission characteristics associated with the location. 7. The system of claim 6, wherein the root node is configured to determine a priority for a content item in the list of content items based on at least the network transmission characteristics. 8. The system of claim 6, wherein the network transmission characteristics comprise at least one of: a data rate, a latency, a capacity, and a cost. 9. The system of claim 5, wherein the location is received from a device operated by the particular user. 10. The system of claim 5, wherein the location is received from one of the child nodes. 11. The system of claim 1, wherein the list of content items comprises a security requirement associated with at least one of the content items. 12. The system of claim 11, wherein the subset is selected based on at least the security requirement. 13. The system of claim 1, wherein the at least one child node is configured to determine the update for the list of content items by searching for a location of at least one of the content items. 14. The system of claim 1, wherein at least one of child nodes is instantiated at a geographic location proximate a predicted future location of the particular user. 15. The system of claim 1, wherein the at least two child nodes are instantiated at respective geographic locations proximate a predicted travel route of the particular user. 16. The system of claim 1, wherein at least one of child nodes is dedicated to the particular user. 17. A method for maintaining content lists, the method comprising: at a parent node interconnected by at least one data network with at least two child nodes and a device operated by a particular user: storing a list of content items expected to be of interest to the particular user; transmitting an update for a subset of the list of content items to at least one of the child nodes, the subset selected based on at least a predicted future location of the particular user and a geographic location of that child node; and receiving an update to the subset of the list of content from at least one of the child nodes. 18. The method of claim 17, further comprising populating the list of content items by identifying content item expected to be of interest to the particular user. 19. The method of claim 18, wherein said identifying comprises processing data reflecting content items retrieved in the past by the particular user. 20. The method of claim 18, wherein said identifying comprises processing data reflecting content items retrieved in the past by other users. 21. The method of claim 18, wherein said identifying comprises receiving a contact list for the particular user. 22. The method of claim 21, wherein said identifying comprises processing data reflecting content items retrieved in the past by users identified in the contact list. 23. The method of claim 17, further comprising predicting a future situation for the particular user. 24. The method of claim 23, wherein the future situation comprises at least one of: a predicted user location, a predicted user activity, and a predicted application executing at a mobile device of the particular user. 25. The method of claim 23, further comprising receiving data reflective of the future situation from at least one of the child nodes. 26. The method of claim 23, further comprising identifying content expected to be of interest to the particular user based on the future situation. 27. The method of claim 17, further comprising: determining a priority for a content item in the list of content items based on at least how soon the content item is expected to be of interest. 28. A device for maintaining content lists, the device comprising: a network interface for interconnecting with at least one data network; memory storing a list of content items expected to be of interest to a particular user; and at least one processor in communication with the network interface and the memory, the at least one processor configured to: transmit an update for a subset of the list of content items to another device by way of the network interface, the subset selected based on at least a predicted future location of the particular user and a geographic location of the other device; and receive an update for the subset of the list of content items from the other device.