This research focuses on three main objectives. First, we want to design, implement and evaluate information retrieval (IR) systems able to work within the blogosphere (e-mail or related domains), where documents (parts of web pages) would be very short compared to the more traditional test-collections. Second, we want to undertake a more elaborate investigation of opinion-finding IR systems. In this case we will target users who may want to know certain objective information concerning a target entity (or product, service, person). The retrieved system would have to clearly identify the retrieved answers as being factual. On the other hand, the expected answer could be an opinion (personal experience with respect to a product/service or personal opinion(s) on a target entity). In this case we want the IR system to classify the retrieved answers according to their polarity (positive, negative or mixed, showing a variety of opinions). Third, we want to design and implement an opinionated IR system on a macro level. We want to provide answers to questions such as "What are the principle opinions expressed in this document?", "Is this web site in favor or against a given topic?", "Does this document (web site) express homogenous opinions on a given target?" For all these questions we need to summarize a set of opinions or reactions to a given target topic.