If you work in an environment filled with friendly, fascinating people, where you continually hear about exciting news (local, online, and around the world), and you are encouraged to be witty and playful, then you don't need Twitter.
However, I work in a cubicle in my house (really -- I had a surplus Herman Miller cubicle installed here) and the cats have their limitations as colleagues.
Thus, five or six times a day, I Twitter. I take a look at what people are saying, throw in some of my own teasers, check "@" replies, answer publicly posted questions, and look at private "direct mail" I receive. My Twitter breaks correspond to the pattern I followed when I worked in a traditional office: Greet people on arrival, mid-morning coffee break, lunch, mid-afternoon break, and departure in the evening. The one addition is that I'm likely to check Twitter once or twice in the evening -- by which time most of us are talking about what we're cooking for dinner or what activities we're up to (shopping, yoga, classes, crafts, dealing with the kids, etc.)
Who, you might ask, are these people I'm Twittering with? Well, unlike the real office where you are usually stuck with a few folks you don't want to deal with, on Twitter you hear only from the people you want to hear from -- you select the individuals you follow.
I've selected colleagues from my past jobs in tech, clients and colleagues from my current SEO work, leaders in the Seattle social media and blogging field, some bellydance, yoga, and fitness folks, and -- here's the twist -- their friends. This "second tier" of Twitter is where it gets really interesting. I see my friends commenting on other people's remarks, and I get curious about the other people, who often get curious about me, and the next thing I know we're exchanging tips on everything from cooking to software. Or meeting in Ballard for lunch.
Twitter is also a great way of keeping up on what's going on with friends from out of town. This way you don't end up finding out, months after the fact, that they've changed jobs, moved, or split up with their significant others. You pick it up on Twitter, and can jump in with an appropriate private direct message.
I most often use Twitter from a web browser, but there are a variety of third party apps that let you read and post Tweets from a smart phone. (This list includes desktop widgets and smart phone apps.) I use PocketTweets but also use Twinkle, an app that lets me see other Twitter/Twinkle users within 1 mile, 2 miles, 5 miles (you get it) from wherever I am. It's fun during an event (such as Folklife) or when you're traveling. Or during a snowstorm, when you want to know what's open in the neighborhood.
Yes, some people do take Twitter a bit too seriously. Some try to game it as a social networking tool, posting a bunch of marketing messages thinly disguised as clever repartee. (It's like having a colleague at work suddenly launch into an attempt to recruit you into their religion, or sell you Amway products.) Fortunately, Twitter makes it very easy to "unfollow" these folks. And I do. (I'm not selective about who follows me, but Twitter offers a blocking tool for people who are.)
The competitive types get all excited about Twitter Grader, which ranks your influence within the Twitter community. I don't know what the grading algorithm is, but I suspect it looks primarily at the quality of your followers (how long they've been on Twitter, how often they post, and how many followers they have).
There's a trend towards merging all your online communications into one dashboard, so you'll see people having their Tweets appear on their blogs, or on Facebook. That's too large, and too uncontrolled an audience for me. What happens on Twitter, stays on Twitter, as far as I'm concerned.
