Into the information firehose that @louisgray speaks of.
In an early talk by Laura Fitton, @pistachio, was the idea that Twitter was a stream to dip into, not a flow to fully consume. You don't try to back up and catch it all, you just dip in and take from what's flowing by at the time, like channel surfing on TV. (Well, at least some of us remember pre-Guide channel surfing).
My way of doing this is to read Twitter once or twice per day. I usually read it in the morning and, occasionally, a time or two throughout the day. Maybe more on days like a holiday when I have more free time. I generally read back a little way into my stream of followees, typically covering the most recent hour or two of posts. There are some followees that I will click on to read further back in their stream. Those tweeters are likely to be a news web site, almost never an individual with the exception of a few bloggers. That way, I catch up on their stories of the day and not just what they published in the last hour or so.
In fact, since I tend to read Twitter early in the morning, it's heavily slanted toward Great Britain, so selective reading back on some streams helps balance that out.
For Facebook, I generally only look at the Facebook gadget on the home screen of my Nexus One Android phone. That gadget is on the far left of the five screens, way over there with the music player, photo gallery, Shazam and such, so it's not where I normally go on the phone. I may click through recent wall updates that appear there, but it's only a handful. I probably do this less than once per day and just at random times.
After looking, I might actually click into the Facebook app itself and read more comments or reply to something. This makes my reading of Facebook a similar dipping into the stream. I don't keep up with everything that would appear on my Facebook page because I rarely log into it, maybe once or twice per week. But then, I describe myself as far less than a fan of Facebook.
The other way I interact with Facebook is through email when someone messages or posts to me directly. In that case, I probably do log into Facebook, via clicking on the link in the message (watch for phishing attacks!!), to reply or read further.
I don't use notifications at all (well, almost), so I'm not interrupted by beeps or buzzes or popups. Google Talk and Chat are silent in my configuration.
For years, I've maintained the practice of not using any sort of new-message email notification. I read email periodically throughout the day. Admittedly, I may check email more than once an hour, but it's part of my job. If I'm consciously trying to achieve more productivity, at a higher than normal level, I try to limit looking at email to less than once per hour or I wait until I've completed a timed session of working on a task. Usually I zero out my inbox in the morning so it's only additional messages that come up during the day. Also, my email is very heavily filtered, so I only see the most important messages anyway.
A side effect of this practice is that meeting notices that arrive in less than 24 hours may not work for me. Asking for more than 24 hours notice for meetings has been a standard request of mine for decades.
As far as chat goes throughout the day, I try to keep a browser tab visible, sticking out somewhere on the computer screen, typically out of the way over on the edge. There won't be an audible cue if there's a chat message, but I should eventually see the tab blinking if I happen to glance over that way. That's the closest thing to an interruption I get during the day.
There is one more exception to the above. My Nexus One Android phone does chime or buzz when I receive a text or chat message. Those tend to be almost exclusively from family or close friends, so they are the equivalent of an important phone call and only occur rarely thoughout the day.
So, to answer Louis Gray's question, I wasn't interrupted at all while reading his excellent post. 8-)