Years ago, customer information was kept on rolodex cards or ledger sheets. Today the web-based equivalent is the Customer Relationship Management (CRM) system. They're still about as exciting and visually appealing as a rolodex card, but just as invaluable. For instance, in our business, all our customers contact information is in our CRM, as well as their website information: who the name registrar is, what Joomla components they have installed, which software licenses they've paid for, etc. This enables any of our team members to gain access to this critical information wherever they are.
In the PC-centric days of the 1990s, the big names in CRM were ACT and Goldmine. Today the largest web-based CRM provider is Salesforce.com. Since we're big open-source advocates we use what's probably the top open-source CRM product: SugarCRM. It comes with a useful standard set of client fields, and custom fields that our particular business needs can be added with relative ease.
Takeaway question: how does your business handle your customer information? Is it time to look at updating it? If so, we'd be glad to talk with you about it.