Yesterday, Mark Nottingham released LCI for the Squid cache (http://github.com/mnot/squid-lci).
LCI (Linked Cache Invalidation) is virtually identical to the LHIC stuff I laid out in the WS-REST 2010 paper earlier this year. Mark was actually working on his LCI implementation even before I started writing the paper - which I didn't know at the time. That's a cool thing to find out about, though :)
The only real difference between LCI and LHIC is the name of the link relations used i.e:
invalidates vs dependant
invalidated-by vs dependsOn
I think I prefer the names Mark picked, and given that they are exactly the same approach it makes sense to give up one set of terms. This is why LHIC will now simply be referred to as LCI or The Mechanism Formerly Known As LHIC.
It's great to see an actual implementation getting released into the wild.. definitely looking forward to playing around with it over the next few days and seeing what people make of it.