Should I denote that a method satisfies an interface?

Question

When writing a class which has ("satisfies") 1 or more interfaces, should I note somehow (e.g. in an XML comment, or with an attribute) that a particular method was added for one of the interfaces?
For example, the IComparable interface requires an int
CompareTo(Object) method.
I know I don't need to do anything other than implement the appropriate methods, but for maintainability and ease of understanding are there any "best practices"
for letting others know why the method exists?

Answer 1

Yes. Your inclination is sound. You should leave a comment in the method's source code and/or larger documentation.
// Implements IComparable interface
in the method source should do the trick, allowing those who will be reading the code closely (you later on, or someone else maintaining, modifying, or adapting it) to easily and rapidly acertain why the method exists.
If the method is part of a promoted API, it can also be mentioned in the API docs (the form of which will vary based on what documentation system you're using).
Even if you're not fully committed to literate programming, in which
an explanation of the code is considered co-equal to the code itself, it is an excellent practice to use comments in the program source and notes in the API documentation to explain how the program works, why it is defined and implemented as it is, and how
to use it.