1. Page http://docs.mongodb.org/manual/reference/method/Bulk/#ordered-and-unordered-bulk-operations
has multiple links to
http://docs.mongodb.org/manual/reference/limits/#Bulk-Operation-Size
in the sentence

Each group of operations can have at most 1000 operations

but that html fragment does not exist.

2. Page http://docs.mongodb.org/manual/reference/limits/#Write-Command-Operation-Limit-Size says that

Write commands can accept no more than 1000 operations. The Bulk() operations in the mongo shell and comparable methods in the drivers do not have this limit.

but Ordered Operations and Unordered Operations both say there is a 1000 operation limit under the covers, so there is a discrepancy here.