Carnegie Mellon University's Computer Science Department was the home of first Coke machine connected to the Internet and left after CMUs soda distributor stopped selling bottles that fit the fabled machine sometime around 1992.
The CS department's coke machine was originally hooked up to CMUA, a PDP-11 that was the department's main system via micro-switches starting in 1985. Eventually, CMUA's fingerd was hacked to enable people to know if the machine was full and the sodas were cold (finger coke@cmua). This whole hack was done because a lot of people got tired of walking all the way to the machine, only to find that it was empty or even worse...had warm soda.
Along with the Coke machine, its neighbor, an M&M machine was also connected under the name "junk food" (jf). Today the 5th Coke machine interface is being worked on by CMU students who have yet to put it up...
Sources
http://www.cs.ucsd.edu/users/bsy/coke.history.txt
http://www-2.cs.cmu.edu/~coke/