Working with my current company I really notice you can use Google Docs and Office Docs that are setup and circulated regularly are a good indicator of potential systems that need developed or possible 3rd party systems that need researched.
When you see a spreadsheet that is commonly used or passed around it may signal a need for new feature in existing system or a completely new system.
A spreadsheet or other office document can really be a basic prototyping process of new systems and how users need or will adopt the new tools. It is a low cost way to immediately start getting the job done and in the language users understand. Everyone knows how to use a spreadsheet right?
Of course you shouldn't think every document needs replacement by a system, but through basic monitoring and information gathering you can really help flush out what tools your staff needs to get their jobs done.