You’re the fourth person on a tech site, out of five who commented, who didn’t even know it existed. That’s pretty telling.
It's not really a tech tool though, and probably isn't marketed to tech people. It's a 6 month old Pinterest-but-for-shopping type of mash up. It's not really out of line for the developer crowd to not know it (or to have read the press release back in July and promptly forget it).
Plus I think there was an article on here a week or two ago about how hard it is to compete with Pinterest...
Not only that but I can't even find it going to look for it. amazon Prime page ^F "spark" returns nothing, Search on Amazon returns energy drinks and other items by that name, the android app doesn't seem to have it either.
It might actually be useful if it has good search & discoverability for products, but if no one even knows about it...