1. A method on a mobile device of providing keyword-based services to message recipients, the method comprising: receiving a text message at a mobile device of a user; identifying a plurality of keywords in the received text message, wherein at least some of the plurality of keywords are identified by comparing words in the text message with a keyword inventory that is maintained on the mobile device; retrieving a market segment of the user, the market segment determined based on observed user activity on the mobile device and further based on profiling messages received by the user; selecting a subset of the identified keywords based on user-specific information, including the market segment of the user, stored on the mobile device; displaying the received text message to the user of the mobile device, wherein the text of the displayed message is formatted to distinguish the subset of identified keywords in the text from non-identified keyword text in the displayed message; associating each of the subset of identified keywords with at least one advertisement and at least one contextual service; receiving a selection of an identified keyword in the displayed message by the user; displaying to the user at least one advertisement and at least one contextual service associated with the selected keyword; receiving a selection of a displayed advertisement or contextual service from the user; invoking the selected advertisement or contextual service to request additional information associated with the keyword, wherein invoking the selected advertisement or contextual service comprises transmitting the user-specific information to the selected advertisement or contextual service provided that the user has authorized such transmittal; and receiving information associated with the keyword from the selected advertisement or contextual service and presenting the received information to the user.
1. A method on a mobile device of providing keyword-based services to message recipients, the method comprising: receiving a text message at a mobile device of a user; identifying a plurality of keywords in the received text message, wherein at least some of the plurality of keywords are identified by comparing words in the text message with a keyword inventory that is maintained on the mobile device; retrieving a market segment of the user, the market segment determined based on observed user activity on the mobile device and further based on profiling messages received by the user; selecting a subset of the identified keywords based on user-specific information, including the market segment of the user, stored on the mobile device; displaying the received text message to the user of the mobile device, wherein the text of the displayed message is formatted to distinguish the subset of identified keywords in the text from non-identified keyword text in the displayed message; associating each of the subset of identified keywords with at least one advertisement and at least one contextual service; receiving a selection of an identified keyword in the displayed message by the user; displaying to the user at least one advertisement and at least one contextual service associated with the selected keyword; receiving a selection of a displayed advertisement or contextual service from the user; invoking the selected advertisement or contextual service to request additional information associated with the keyword, wherein invoking the selected advertisement or contextual service comprises transmitting the user-specific information to the selected advertisement or contextual service provided that the user has authorized such transmittal; and receiving information associated with the keyword from the selected advertisement or contextual service and presenting the received information to the user. 11. The method of claim 1 , further comprising a keyword inventory that is maintained on one or more network servers, wherein identifying a plurality of keywords in the received text message includes receiving an identification of a keyword from the one or more network servers.