People are smoking synthetic weed because a) it is, or was legal and b) it doesn't show up in drug tests. The high from it is nothing like a marijuana high IMO, and is really scary. Like, one or two hits gets you really high, but in a bad way. I would never smoke it again, but there a lot of people who refuse to believe it's not safe, even when you point out to them that no one really knows what the long term affects are. The guy who invented it says you're an idiot if you smoke it, because even he can't tell you what it will do to you. It's some nasty shit, but people are still smoking it--one of my sister's friends is about to go to court for possession because he didn't realize it was no longer legal here.