The question 'How long could you survive?' could, for me, be answered in a number of ways. I probably could survive for some time, but what would be the impact on my life if I had to?; profound I'd say
I've had an ISP subscription since 1995- good old BTInternet at 9.6, then 14.4 then up to 56kbps over a modem/phone line, followed by Cable Internet and now a BT LLU service which averages 6.5Mbps at home, and a BT Business connection at work which also gives 6-7Mbps.
Through these generations of service supply we've seen an ever increasing reliance on the WWW for both 'infotainment' and business use. At work, my new clients coming via a web search comfotably exceeds those using paper based directories and many use email as a 1st point of contact. While working, the on-line postcode form fillers and automatic SMS reminders have made life a lot easier and the ability to do research in front of a patient is now an essential part of business. I've been fortunate that the longest outtage I've seen over the last 7 years is about 2 hours.
For out-of-office business use, having a WM device with a Microsoft Exchange Connection which also syncs to my office diary has freed me to leave the office if I want to, knowing my admin can be acheived using my mobile device and telephone call diversion.
At home, the whole family is 'net aware', even my wife who abhors anything computer related, though she still appreciates the necessity it has become. I can't think of an evening when something we see on TV has not prompted a 'what was he in before?' or 'who sang the original of that?- look it up on the internet' has not occurred. This is usually quickly acheived via the ever present XDA Flint using a mobile browser. Every holiday we have taken since 1997 has been booked via the internet or email, and increasingly all our major household purchases have been researched and bought via websites.
I mustn't forget also that entertainment, whether via 4Winmobile or using sites like iPlayer, Napster or AudialsOne is now derived largely from the internet.
So, how long could I survive without it? The short answer is not long, without seriously compromising both home and business tasks!