>C++11 is the first version of the language to feature a built in hash table. One has to wonder why the language is only now gettin (sic) such a basic data structure as a generic hash table.
That's because C++11 is the first major revision of C++ since 1998 (yeah, blame the ISO committee). Hash maps have been present in various non-standard ways in C++ stdlibs since 90-s. That's also the reason they are called 'unordered_maps' in the C++11 to avoid all kinds of name collisions.
You might also notice, that tree based std::map has been present since C++98.