In the October 2010 edition of MSDN Magazine, Julie Lerman's Data Points column (Entity Framework Preview: Code First, ObjectSet and DbContext) refers to a method as being "just not discoverable".
What does she mean?
I presume that it means "easy to find and then to know what it does and how to use it", but not sure.
Is this an extended use of 'discoverable' that originated with the way the word is used with web services?
I think your guess is right. It's just a trendy way of saying 'easy to find'. And as 'find' and 'discover' are roughly synonyms, it's not completely absurd. In the context of modern API design, people tend to mean "when the user presses the . key, will they easily be able to guess which item to choose from the Intellisense listbox?"
I don't think it's derived from anything to do with web services - it's just that the phrase 'service discovery' has the same roots, and perhaps sounds better than 'service finding'.