Being your own customer

Recently I’ve been idly thinking about companies that have the good fortune of being their own customer. I think this is an extremely valuable place to be, because it gives you the best possible insight into your product, and insulates you from losing touch with your product’s market.

Some examples I think of:

• Salesforce's use of their own CRM product with a team of salespeople that sell their product. Not only do they get great feedback on their own product, but the fact that they have a best-in-breed sales team is great marketing itself, and they get to be a thought leader in their space.
• I bet Dropbox and Box use their own file-sharing services internally. By doing this, they get great insight into how a corporate might use their product and what features they'd need. Same with Evernote and Google Apps.

I wonder though, if this is possible only for B2B (or even more narrowly, enterprise) products. Can consumer-product companies be their own customers. Of course their employees can; but is that enough?