Origin of 'shipper'?

· Miscellany

Reading a Buffy spoiler fan website today, I encountered an unfamiliar term: shipper. I know what slash fiction is (having stumbled on a book about k/s fanfic in the Princeton library a good 20 years ago), and I gather a shipper is someone who either likes to write slash fiction or who at least likes to read it.

See Carnal-Sins, for an example of a Spike/Buffy shipper site.