what exactly are steam vacuum cleaners?

zei.zei need help to clarify doubt about: : what exactly are steam vacuum cleaners?
im just really curious about it and whats the difference with the conventional vacuum cleaner?is it worth buying?
but is there anything needed to put in it..or it just uses water?

Try this:

Answer by Foster DAD
Depends on the useage.They put out steam and suck it back up with dirt. Problem is too much steam may cause mildew in a carpet. Another type uses a water cannister instead if a bag. They are excellent because dirt & dust goes into the water to be tossed out instead of filtering back into the air as conventional vacs do. Believe not recent TV ads. they are not the origional nor the best. I have had a better one for many years.

Know better? Leave your own answer in the comments!