A friend asked for suggestions on keeping up with floods of email, so here's how I manage my inbox. It's in a constant state of revision and improvement, and I don't always follow it religiously (actually, the way I tell whether a procedure is "improving" is by how much I do stick to it), but this represents a few iterations of procedure and it's far better than the "check it whenever, panic, let things pile up" methodology I had a year ago.
My current email-procedure owes a lot to a whole slew of people and resources that inspired it; off the top of my head, there's the Inbox Zero series on 43folders, Lifehacker, and David Allen's "Getting Things Done" book. If folks want, I can try to post a roundup of these links later on.
1. The first thing you do when you wake up should NOT be checking your email. I'm not allowed to hit my inbox until I've done something in the morning, whether that's finish a task or two for work, read a book, work out, shop for groceries... anything I consider to be productive. Sure, it's a carrot on a stick, but it means I get something done for the day, if nothing else.
2. Batch-check your email. I try to check my email as few times as possible per day - my current goal is 3 times a day, once in the morning (after completing my first productive-thing), once after lunch, and once before leaving work for the day. Sometimes if I've been good I'll let myself hit it again before I go to sleep (but this is dangerous, since you might end up spending several more hours online if you get sucked in...) Of course, if you need to search your email archives
"Less checks a day? How can that help to keep up better?" It takes time to switch between tasks, and "checking email" is a task; it takes a few seconds to get into "email mode," and switching back and forth between "email mode" and "something-else mode" adds up throughout the day. If you set aside time to Just Do Email, you zoom through it much faster (because you know you won't do anything else until it's done). Also see the discussion on threading, below.
3. Use an email client that supports threading. I use Thunderbird, with Pine as an "I'm not at my laptop and need to ssh in" alternative (though I'm switching back to Mutt soon as I find that I prefer it). A lot of emails string themselves out into long discussion threads, and if you can treat each thread as an attention-object (rather than each individual email), you save a lot of time. You also get the chance to read the perspectives of multiple people before chiming in with your own thoughts (which may be more level-headed after reading the reactions of others). Another way of thinking about it: instead of replying 20 times to 20 emails on the same topic, you can reply 1 time to a 20-email discussion thread on 1 topic. Guess which one takes longer?
4. Use canned responses. If there's something you find yourself typing over and over again, type it one more time, save it somewhere, and make it easy to copy-paste or autoinclude it in (better yet, put it on a public-facing webpage if you can, and set up a quick-response email with the link). This is an extension of the idea of email signatures, which many people have autoincluded already. Do you keep having to give people directions to your house? Instructions on how to connect to IRC? I use the Quicktext plugin within Thunderbird for this.
5. When you go through your inbox, finish going through your inbox. Every single message that's hit you in the meantime should be replied to (if you can do it within a few minutes), deleted, filed somewhere, or put in a "I need a lot more time to reply to this" section (which then becomes part of your to-do list). Another way of putting this is that there should never be any non-new messages in your inbox; the first time you read something, act on it in such a way that it moves OUT of your inbox. In practice, this is where I usually slip, and I'm actually beginning to move towards "when you go through your inbox for the last time each day" rather than "when you go through your inbox." But the principle of trying to keep your inbox clean remains the same.
6. Download your email as seldom as possible, and do email offline as much as possible. This is something I started doing out of necessity when I was in the Philippines, where internet access is far less prevalent than on a high-tech college campus (for instance). I find myself distracted by the internet, and I also find that I batch through things more quickly when I download my mail, read it offline, reply to everything I can, cache the other emails in my to-do list, connect to the internet and send all my replise at once, and then move on to something else.
7. When you travel/get hosed, set an autoreply, and DON'T CHECK YOUR EMAIL. Do a big batch when you get back to breathing room instead. In the meantime, let people know that you might not respond for a bit. (I'm really bad at this, mostly because I don't realize I'm hosed until it's too late - but I do set retroactive autoreplies when I realize it now.)