14. A computer readable storage medium storing a program of instructions executable by a machine to perform a method of contextual text adaptation, the method comprising: identifying a target user; receiving a corpus of documents in context of the target user; receiving a dictionary of words; receiving a dictionary of synonyms; generating a topic model algorithm based on the corpus of documents and the dictionary of words by machine learning, the topic model algorithm comprising a first function that predicts probability distribution of a plurality of topics in a given document, and a second function that predicts probability of a given word occurring in a document associated with a given topic; and storing the first function and the second function of the topic model algorithm in a storage device, receiving an input document; determining input document topics associated with the input document and a normalized weight associated with each of the input document topics by executing the first function; for each of a plurality of input document words in the input document, determining a probability that an input document word is associated with an input document topic for each of the input document topics by executing the second function; determining an aggregate probability for the input document word as a sum of products of the probability that an input document word is associated with an input document topic and the normalized weight of the input document topic; determining a synonym of the input document word based on the dictionary of synonyms; determining an aggregate probability for the synonym; comparing the aggregate probability for the synonym and the aggregate probability for the input document word; responsive to determining that the aggregate probability for the synonym is greater than the aggregate probability for the input document word, replacing the input document word with the synonym; and generating an output document comprising content of the input document with replaced words.
17. The computer readable storage medium of claim 14 , wherein the corpus of documents are received over a communication network from a social media server.