Not for me, daftpunk - it's due to being bullied when I was a teenager (when the internet hadn't been dreamt of, let alone invented) to the point of being suicidal, and having my parents ignore my plea for help, leaving me feeling that no-one would listen to me or help me - so I went on being bullied throughout senior school. It is no exageration to say that this has blighted the rest of my life.
I believe it predisposed me towards getting PND - that, plus the fact that I never managed to breastfeed successfully, so I felt like a total failure as a mother - unable to feed her own babies, not able to do the things other mums were doing, worrying that my boys were suffering because of me - wondering if they'd all be better off without me.
My marriage has suffered - dh has to pick up a helluva lot of slack round here, because there is only so much I can cope with; and is tired and stressed from work, has to cope with a wife whose mood is always low, and who has zero sex drive. If I were dead, he could find someone who'd be a proper wife to him and a proper mother to his sons.
I believe I've failed the boys - I should have read with them more, done more crafts and art, done more jigsaws, played more games, done baking with them - I did do these things, but not enough, in bleak remembrance.
I find it very hard to get out of the house and meet people - I don't see why anyone should want to talk to me or be my friend, and mumsnet is literally a lifeline - people here will talk to me. So no, it's not too much time on the internet for me.