Yahoo! Instant Messenger saves chat messages in a DAT file extension format in archives on your computer. DAT files are generic data files created by a specific application and can only be used by that application. They include text in binary formats. In order to view saved DAT text chats archived in Yahoo! Messenger you need to decode them. This simple process can be accomplished with an easy-to-use decoder program that allows you to view and read them in HTML format. Writer Bio

How to Read a Yahoo Messenger DAT File - 59