12. A computer-readable storage device storing instructions which, when executed by a processor, cause the processor to perform operations comprising: performing an analysis of a history of communication sessions over two communication modalities, wherein the analysis considers a semantic meaning of the communication sessions, a temporal relationship among the communication sessions, and a user activity that transitions from a first communication session to a second communication session, wherein the first communication session and the second communication session are part of the communication sessions; identifying a relationship among the communication sessions based on the analysis; prioritizing the communication sessions based on the relationship to yield prioritized communication sessions; generating a unified communication log based on the prioritized communication sessions; outputting the unified communication log to a user; processing feedback from the user to yield processed feedback, wherein the feedback from the user comprises an observation of how the user interacts with the unified communication log; and based on the processed feedback, adaptively adjusting how the communication sessions are prioritized.
12. A computer-readable storage device storing instructions which, when executed by a processor, cause the processor to perform operations comprising: performing an analysis of a history of communication sessions over two communication modalities, wherein the analysis considers a semantic meaning of the communication sessions, a temporal relationship among the communication sessions, and a user activity that transitions from a first communication session to a second communication session, wherein the first communication session and the second communication session are part of the communication sessions; identifying a relationship among the communication sessions based on the analysis; prioritizing the communication sessions based on the relationship to yield prioritized communication sessions; generating a unified communication log based on the prioritized communication sessions; outputting the unified communication log to a user; processing feedback from the user to yield processed feedback, wherein the feedback from the user comprises an observation of how the user interacts with the unified communication log; and based on the processed feedback, adaptively adjusting how the communication sessions are prioritized. 17. The computer-readable storage device of claim 12 , wherein the communication sessions comprise one of an email, an instant message, a telephone call, a voice-over-Internet-protocol communication, a text message, a social network communication, a document, a collaborative interaction, and a multimedia interaction.