Recently I found myself, half by intent and half by circumstance, cut off almost completely from the internet. No email, no twitter, no HackerNews. I don't have TV or cable. I also refused to answer my cellphone, handing it over to a friend to monitor. (He knew how to contact me in an emergency).
And.. I loved it. A few withdrawal symptoms for the first few days, but I've never been so productive in my life before.
I'm thinking of making this kind of isolation + total focus a big part of work going forward. I'm thinking of going into "Alternate 4-6 weeks of focused work in isolation with 4-6 weeks of connected, 'normal' existence" mode (with few days of travel to random places in the middle).
Which might be really soon. I have a pile of mathematics texts to work through. My initial efforts to learn mathematics enabled me to break free of the 'take some random US business's database and build a web front end and call yourself a software engineer' phase of my career, and make a living writing interesting programs for interesting people doing interesting things. Now is a good time to ramp up on the math (and then write more interesting programs doing interesting things. ;-). Rinse. Repeat.).
Mostly my work (post the wasted enterprise dev years) involves a lot of programming and a little math. This year the ratio might be inverted. A scary, if exhilarating, thought - I find creating proofs way tougher than creating programs. With a good maths text, half a page is often a good day's progress. But on the other hand, it feels somehow more fundamental and satisfying.
One doesn't really need the internet to work through math texts. You don't even need a computer. You need a pile of paper, pens, and a good place where you can work undisturbed.
I did miss some of the news - I didn't get to know of Aaron Swartz's suicide for instance (poor fellow, R.I.P) and the latest shenanigans of India's dysfunctional government, or the French invasion of Mali. But by and large, the world didn't change all that much in 6 weeks, and not having to follow or respond to a constant stream of news and tweets and emails and phone calls is a refreshing experience.
The one complicating factor in all this is the prevalence of compelling MOOCs put out by Coursera, EDx et al. For 'attending' a MOOC, you need the internet, and then it is all too easy to drop into checking email, or peeping at Twitter and then you are back in the roar of the world flowing by. I don't quite have a solution yet. Working on it.
 Phone calls are worse than any other communications medium because the damn thing actually *rings* and jerks you out of the zone to deal with (mostly) trivia. Switching into silent mode every time you want to do some work is a major pain, because (on my phone) you have to go through multiple button presses to accomplish the mode change. And then if you see a friend's missed call you feel guilty if you don't call back. But if you don't see anything, you can just get on with work and apologize later ;-).