Well, I just checked in the Camel books. The 3rd edition does indicate "require Exporter;" in modules, but the 2nd edition (which I learned from) has "use Exporter;" in modules in most of the examples (although there was a "require Exporter;" in an example.) Randal Schwartz's book "Learning Perl Objects, References & Modules" says "...As a module author, all you do is add:

use Exporter;
our @ISA = qw(Exporter);
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I just made a module skeleton using h2xs, and "require Exporter;" appears in the module file. So maybe either will suffice..I'll go with the "require" form since that's what h2xs produced.
chas
(Update: Hadn't seen Dragonchild's reply yet - that seems to settle the difference. Fixed typo.)