Did you know that Google has made over 700 million Usenet messages available online - and searchable? It's a great way to find out what people have been saying about your company's products.
(What is Usenet? Usenet is a world-wide distributed discussion system in use since 1980. It consists of a set of "newsgroups" with names that are classified hierarchically by subject. "Articles" or "messages" are "posted" to these newsgroups by people on computers with the appropriate software.)
For example, to find out what people are saying about your company, go to the Google Groups search at http://www.google.com/grphp?hl=en. Then, enter the brand name, product name or company name you are interested in.
This technique can also be used to see what people are saying about competitive brands.