about 1500+ hours on the forum
almost 2000+ hours on the game... this isn't exact and is most likely more, far far more but due to it being offline mostly I can't track it through steam
10-ish hours drawing (and failing haha, i wanted to have a go in the compedium but meh)
and probably 300 hours on Microsoft word typing up rich detailed Terrarian lore stories :3
My steam only says I've pled like 200 hours but most of my terraria playing was offline just faffing about in single player to pass the time between school and sleep. I guess after I got internet I'd done everything so I didn't really play.
It's not that much of an impressive figure compared to most of the true Terraria Veterans on here but I'd say I clock in around 4000 hours worth of stuff across my Terraria playing which started a good 4 months before 1.1 was released. so yeah that's my answer for how much time Terraria has taken away from my life haha...
4000+ hours
EDIT: I COMPLETELY FORGOT YOUTUBE! I have watched probably 500 terraria videos each around 15 mins. I am too lazy for maths but someone can probably add that too it in there head.