What is this long-nosed ferrule for?
 

I bought a set of Shimano shifter cables, and it included several ferrules. One of them looks like this:
https://cimg8.ibsrv.net/gimg/bikefor...4a5d7c68e4.jpg
What is this used for?

11 speed shifters

I think it's supposed to help keep dirt and gunk out.

ferrules with snouts go at the transition between housed cable and bare cable - the snout is supposed to minimize crud from the bare cable being carried into the housing as the cable moves back and forth

IIRC, these ones are usually used at housing to bare cable transitions near the rear derailleur. I use them everywhere where I can to keep water spray out in winter.

these go IN the brifter, there is a slot where the housing goes in

See Shiamno's Dealer's Manual at http://si.shimano.com/pdfs/dm/DM-ST0002-04-ENG.pdf

What now? Tell me more.

The dealer manual is always the first place to start for any question about Shimano parts or mechanics.


-Tim-

This!

There are different versions of these and some are used at the derailleur, but the one in your pic that has the spine is specifically made to fit in the brifters.