Yes, I actually bought a five-pound bag of this recently. I spent a good two hours rubbing it into my carpets last weekend - which went pretty well, though it would not work on my velvet couch
We had to lock the kitties up in the bathroom while doing it, though, and wear dust mask, as it is completely innocuous (and even benefitial) when ingested, but can cause respiratory problems if inhaled (because it is razor sharp at a microscopic level).
Too soon too tell if it will help with our flea problems, I have to wait til I can put another dose on Revolution on the cats to judge (I got them the kitten size the first time, but they are obviously well over 5lbs now, so I guess it is not working as well as it should be).
I will invest in a salt-box to sprinkle it more easily though, because by hand it can end up being really hard to rub it in an homogenic way, without causing your carpet to look dusty (you do have to reapply it every time you do a thorough vaccuuming too).
That's the extent of what I know about it (besides the fact that I can never spell it without copying and pasting it)
Hope this helps!