Tag
Sometimes in a WinForm, you need to associate a bit of data with a UI control. Control.
Tag then becomes useful.
I'm sorry, but I disagree. It is my opinion that the Tag property should be buried as soon as possible.
Consider the next person in line to maintain your application. The Tag property is untyped and unnamed, and could cause so much confusion, that it's not worth it.
My solution? Created a derived class for the control and create a property for your information. In my opinion, it's more intuitive.