Complex sentence: Since then, KnujOn.com has been collecting spam samples from the public, not to build better filters or blacklists, but rather to use them for illicit site termination, to test the Internet's policy infrastructure, and gather important statistics.
Split into simpler sentences: Since then, KnujOn.com has been collecting spam samples from the public. Not to build better filters or blacklists, but rather to use them for illicit site termination, to test the Internet's policy infrastructure, and gather important statistics.