Email, chat and almost everything else is just text. All text is searchable. I think what you really want is something that searches email and chat systems for relevant topics and maps them together for your org highlighting things people are talking about. The search system would have to be aware of identities to avoid leaking sensitive information and causing corporate security incidents.
Someone who reads every email, or at least looks at the subject long enough to do something with it (delete, move, ...) and don't leave unread emails in their inbox
