Python is the best "glue" language. Large 3rd party libs, easily readable/writable (even by non-programmers), ld (it predates Java), established, great user community.
So, people in different realms (MSoft IronPython, JVM/Enterprise Jython, restofus CPython, scientists/performance Cython/PyPy,Stackless,Psyco, academics/experimenters many more) all want to use it and make versions that integrate with their tools.
So, people in different realms (MSoft IronPython, JVM/Enterprise Jython, restofus CPython, scientists/performance Cython/PyPy,Stackless,Psyco, academics/experimenters many more) all want to use it and make versions that integrate with their tools.