What makes a vodka filtered 7 times so much better?

The more filtering you do, the smoother the taste. Also, filtering removes impurities and congeners (toxic chemicals that are formed during fermentation, some liquors have more of them than others). Congeners have a lot to do (along with dehydration!) with headaches the next day! Big reason why you get worse hangovers from certain alcohols (for example, brandy has the most congeners of any alcohol, then red wine on down to gin and vodka having the least, generally) or from less expensive ones that are only filtered once. Bad vodka tastes like rubbing alcohol, good vodka should taste close to water.

And yes, it can be partly hype, but anyone who has ever gotten drunk off a bottle of Zemkoff or popov vodka as opposed to (NOT VERY EXPENSIVE, but very good brands) like Sobieski or Svedka or Skyy, or the more expensive belvedere, Grey Goose et al. knows there is a HUGE difference!!

Yeah, top shelf vodka really is better. Take a look at the link. The filtering probably doesn't make it top shelf. That happens somewhere else.

How about these grits, ribs and brisket. I'm betting vodka in lemonade would be money with that.

Summum Vodka

I'm guessing - other than as the first answer so eloquently stated - that it is part marketing hype, and possible part - gawdzferbid - their starting with some really crappy vodka and HAVE to filter it seven times :p

The advertising people who use it as a gimmick. Vodka is essentially a mixture of ethyl alcohol and water and little else. So it really doesn't matter how many times it's filtered. No vodka I've ever seen is cloudy.

Marketing hype, pure and simple. Convince people that there really is a difference between 6 filters and 7 filters and their own vanity will ensure that they never allow themselves to be seen by others drinking your competitors product.

Its not as raw and bitter. It is smoother going down.