I think the examples need to be split into xpath expressions that do selecting and those that do evaluating.
From Geoff's article:
One issue that I find stalls many first timers as they encounter XPATH is the difference between selecting and evaluating.
XPATH is used in two very different contexts within an Identity Manager solution.
The most common use is to select a node in an XML document. The second usage is to call some function or do something with XPATH. Both approaches use the same language but are very different and confusing.
Watch the Wiki text!
In the strip values section:
The wiki is interpreting the two single quotes as wiki text for italics. I copied and pasted the code and beat my head against the desk for a good half hour! If you look closely you can see that the bracket to the right is italicized.
Should be: <do-strip-xpath expression="add-attr[(double quote goes here)]"/>