RE: http://docs.mongodb.org/manual/reference/method/db.collection.initializeUnorderedBulkOp/#behavior

The second sub-title "Continue on Error" is confusingly close to the name of an option in some drivers WriteConcern.continueOnError. Setting the driver option has no effect on the behaviour of the bulk operators - the behaviour is fixed by the choice of which object is used.

The sub-title of the counterpart object is "Stop on Error". It is clear from reading both that the titles are a terse description of their behaviour but it is confusing for anybody familiar with achieving this behaviour by using the option - to make it even more confusing, a WriteConcern instance is passed to the bulk operators to describe other control behaviour of the operation but through which the continueOnError member is ignored.

I might suggest changing the second sub-title of both pages to be "Error Handling" to remove the ambiguity and bring them into parity. Let the copy explain the difference.

It may also be worth adding a warning to explicitly call out that the "continue on error" behaviour of initializeUnorderedBulkOp is not affected by any driver setting of the same name.