obtaining a communication data stream in which a user of the users participates;

extracting using natural language processing data relevant to a point of view of the user from the communication data stream by use of at least one pre-trained point of view classifier;

generating at least one point of view record of the user based on the data from the extracting, wherein generating includes generating a plurality of historical point of view records of the user responsive to the user and a second user

storing the at least one point of view record of the user from the generating in a knowledge base;

detecting a certain communication instance as being eligible for the communication assistant service, wherein the user and the second user of the users are human users participating in the certain communication instance at a time of the detecting, wherein the generating the at least one point of view record of the user includes generating a plurality of historical point of view records of the user prior to the certain communication instance involving the user and a second user; and

selectively delivering to the second user a certain communication assistant service communication in dependence on processing of the stored at least one point of view record of the user, wherein the processing of the stored at least one point of view record of the user includes processing the plurality of historical point of view records generated by the user generated prior to the certain communication, wherein the selectively delivering to the second user is

performed while the second user and the user are participating in the certain communication instance, and

performed responsively to a first query of the knowledge base, wherein the first query of the knowledge base is selectively performed responsively to an examining of communication content of the second user,

wherein the knowledge base stores topic content according to multiple topics from processing a plurality of source documents associated with the multiple topics, wherein the selectively delivering to the second user a certain communication assistant service communication is performed responsively to a first query of the knowledge base, and wherein the first query of the knowledge base is selectively performed responsively to an examining of the communication content of the second user during the certain communication instance with use of natural language processing resulting in a determination that the second user wishes to know the point of view of the user; and

further selectively delivering to the user a particular communication assistant service communication in dependence on processing of a plurality of historical point of view records generated by the second user prior to the certain communication instance based on communication data streams of the second user during historical communications of the second user,

wherein the further selectively delivering to the user is performed while the second user and the user are participating in the certain communication instance,

wherein the extracting using natural language processing data relevant to a point of view of the user from the communication data stream includes extracting a topic of the communication data stream to provide an extracted topic of the communication data stream, and determining a sentiment of the user in regard to the extracted topic of the communication data stream,

wherein the selectively delivering to the second user the communication assistant service communication includes selectively delivering to the second user data indicating the sentiment of the user in regard to the extracted topic of the communication data stream, and

wherein the determining a sentiment of the user in regard to the extracted topic has included processing historical data from data sources other than the communication data stream.