The only reason I ever booted up the Windows Store is getting shut down. I'd say I am surprised, but I'd be lying.
I had hoped that the community would blow up like other games that have user made content, but the community was tiny. The single afternoon that I spent in Project Spark consisted of going through ~5 user made games that were worth checking out, everything else was crap.
Such a shame too, there was a lot of potential,
I get the feeling MS starts projects thinking: "We're MicroSoft, anything we do will succeed by default, because we're MicroSoft!"
When they fail, instead of putting in effort and improve things, the whole thing is swept under the rug.