Do users write about the system in use?

Social Network Sites have grown considerably in recent years. Studies have revealed that users write in Social Systems about services, opinions or facts concerning personal life. However, no studies have been found regarding the following question: Do users write about the system in use? How? Is it valid to evaluate the users experience in Social Network Sites through their written texts? A methodology to search for postings of users on Twitter was used, composed of filters which combine patterns which may be related to the use of the system. The results have shown evidence that some messages posted in these types of systems are about the system in use. As a contribution, we presented some characteristics of the messages of the users of social networking sites in order to facilitate the understanding of its usage experience.