I was working with a client last week who reminded me of one of my least favorite nuances about SharePoint -- the Yes/No field. It sounds pretty simple right? If you are making a list and you have a requirement to add a field something like, "Are you a robot?" Would seem like a slam dunk for a Yes/No field right??? Technically it would "work" just fine but there's an issue.
You've probably already done this and are thinking to yourself "John, it works just fine." You are right, you probably selected No in your list item and it saved it shows up as "No" in your view. What's actually happened is that behind the scenes that No has been stored as a "0" -- if you had said Yes it would have been stored as a "1."
This causes issues when you try to run searches or use things like the Content Query Web Part (CQWP). The typical user would do something like want to create a CQWP that only shows items where someone had specified "Yes" they were a robot. However, no results would show up because the value they need to be looking for is "1" not "Yes."
To avoid this confusion I strongly recommend against using Yes/No fields and instead suggest people use a Choice field and specify the values as "Yes" and "No" which behaves exactly like you'd expect. No need to mess with 1s and 0s.
JR