title: Overriding Extension Methods
body: <p>I've been thinking about using extension methods as a replacement for an abstract base class. The extension methods can provide default functionality, and can be 'overridden' by putting a method of the same signature in a derived class.</p>
  
  <p>Any reason I shouldn't do this?</p>
  
  <p>Also, if I have two extension methods with the same signature, which one is used? Is there a way of establishing priority?</p>