As posted by @alessandro on IRC:
http://cstheory.stackexchange.com/questions/19759/core-algorithms-deployed/19773#19773
This list is a compilation of those “core algorithms” students have to implement in theory during studies in the real world. Also coming with its real world implications and imperfections. But yes, they are actually implemented in the real world – just they are not the hard problems we have in Computer Science nowadays .