It really depends! My computer certainly runs all day being connected to the www, but I'm not going to spend each day all day in front of it. Sometimes I do, while drawing or reading stuff or simply chatting, sometimes I go off to read a book or play a video or something like that.
Male, between 3 and 6 hours. However, I tend to leave my browser open while I'm working, so much of that 3 and 6 hours is spent with my back to the computer (or with Photoshop open), checking Facebook for five seconds every ten minutes.
Tumblr, watching movies, playing games, drawing, chatting with friends... a lot of things XD I go for short walks with my dog every morning and evening - but hell, it's winter, it's too cold for being out for a long time :C
Pretty much every waking moment, but that's mostly just working while I'm on Skype or have a movie streaming. Web browsing is really just checking email, DA, Facebook, and Tumblr, which I only let myself do before breakfast and before bed, so maybe an hour of that.
A lot of my time it's rather wasting away on the net. I use it productively. Making art, requires you to look at others for inspirations as well. And sometimes in a busy lifestyle, keeping in contact with friends becomes challenging, so facebook and da, makes things a little easier.
My laptop runs pretty much all day except when I'm in class. I like to be available if someone needs to contact me, I have a lot of homework online or in PDFs that I don't want to print (because it would add up to sooooooo much eco-death), and well, FACEBOOK and DA and STUFF. Also games. *hides*
I'm inclined to say 10 hours (who wants to keep track of their hot mess of an addiction really) but it's dispersed into intervals throughout the day. I spend a lot of time drawing on the computer or using my desk, so I'm hooked into the internet quite often.
I'm one of the few that is spending less than an hour. lol But my life is pretty hectic right now and I've had to cut it down quite a bit. Under normal circumstances it'd be about 3 hours per day, mostly going to correspondence with clients.
Like... two hours after I'm done studying and doing classes, on the weekends I'm usually out doing stuff with friends and just spend a little time when I get home, before I go to sleep. 10+ hours? dammnnnnn