Eating your own dog food, also called dogfooding, is a slang term used to reference a scenario in which a company (usually, a computer software company) uses its own product to demonstrate the quality and capabilities of the product. (http://en.wikipedia.org/wiki/Eating_your_own_dog_food)
There are unique process, design, and testing challenges involved when a company "eats its own dog food" while developing a software product. I think a dogfooding tag would be useful.
I like the term and decided to create the dogfooding tag and add it to your question.
As a user you earn the privilege of creating new tags when you ask a question after receiving 300 reputation. I see you haven't quite reached that point yet but I am sure you will get there some day. :)
I thoroughly dislike the term since it is meaningless to me. Describing a product as dog-food is not a compliment. I noticed the use of this term the other week in an email from Telerik and had to look it up since it completely threw me. It still doesn't make sense, and just strikes me as trendy jargon. Perhaps it's a cultural thing.