UNISoN is a Java application that can download Usenet messages from free NNTP servers, show the saved messages, then allow filtering of data to save to a Pajek network file or CSV file. It creates networks using the author of each post. If someone replies to a post, there is a unidirectional link created from the author of the post to the author of the message they are replying to. There is also a preview panel that shows the network visually. It was developed in 2008 as part of an MSc Business Systems Analysis & Design at City University London. and was released as Freeware. In 2016 the code was made Open Source.