I worry about it, yes. Particularly when the user is me.
Or your startup founders?
I assume you have done the math.
Ask PG or RescueTime or 8aweek: how much time has the current YC batch spent on YC news?
Nah. I think in general most users would just watch TV or play a game otherwise.
If someone were spending all their time on http://dfranke.us, I'd not so much feel bad for them as be rather scared and probably call the cops.
Most of the site's I've made in the past have been tools to help my users, so the more a user is on the site, the more are getting at a personal level. Now if it were my blog or something similar, it's their time-I have no room to complain or feel bad. I do the same sometimes when find a new blog or news site I like.
You should rephrase the question.
Would you feel bad if your boss overpaid you(on purpose)?
Not in the least. They have every right to enjoy their memories as much as they can.