A steam vapor cleaner does not vacuum nor does it inject cleaning fluid into fabrics but rather it cleans via steam which is feed out at about 65 psi and at about 220F.
Since it cleans with steam there is very little water left behind in the fabric or on whatever material you happen to be cleaning. An extractor injects either hot or cold water (sometimes mixed with a carpet shampoo) into the carpet or fabric and is then extracted right out again. Some extractors have the ability to be both an extractor and a vacuum.
Hope that helps,
Anthony