Twitter is a fast-evolving, surprisingly powerful new way to exchange ideas and information, and to stay in touch with people, businesses, and organizations that you care about. It's a social network — a digital abstraction that represents who you know and who you're interested in (whether you know them personally or not) — that you can access from your computer, your cellphone, or anywhere with an Internet connection.

Twitter has one central feature: It lets users instantly post entries of 140 characters or less, known as tweets, through the www.twitter.com site or your cellphone, or by way of the numerous applications that are available for both. (We talk more about the different ways to tweet in Chapters 8 and 9.)

On the most basic level, Twitter is a communications network that combines elements of Short Message Service (SMS or texting), instant-messaging communication tools, such as AOL Instant Messenger (AIM), and blog publishing software, such as Blogger or WordPress. Like blogging, your tweets are generally published to the world at large where anyone can read them on Twitter.com (unless you choose a private account, so that only those you choose can see your tweets). Unlike blogging, you're limited to just 140 characters. Like instant messaging, you can communicate directly with people (through direct messages), but unlike instant messaging, each message has its own unique resource locator (URL), so each message is actually a Web page. Instant messaging also lacks the social network "following" features of Twitter and basic ideas like "publish-subscribe" and one-to-many broadcasting of messages. Think you can't say anything meaningful in 140 characters? Think again. Not only are twitterers innovating clever forms of one-liners, haiku, quotes, stories, and humor, but they're including links — in 23 percent of all tweets by one measure — and links carry a lot more information and context. Writing 140-character messages seems trivial. But headlines and very short advertising copy are famously hard to do really well — and the right words can be quite powerful. Consider: "Man Lands On Moon."

The idea of Twitter sounds simple — deceptively simple. When you think about how millions of people around the world are posting Twitter messages, following other people's Twitter streams, and responding to one another, you can start to see the significance behind Twitter's appeal. In fact, Twitter has noticed that it acts like a "pulse of the planet," a zeitgeist of what everyone is thinking about and doing and feeling, right now. Now that's pretty interesting!

True, Twitter can look like it's full of noise. But, once you find interesting people and accounts to follow, your Twitter stream shifts from a cascade of disjointed chatter to one of the most versatile, useful online communications tools yet seen — that is, if you take the time to learn to use that tool correctly.

If you're familiar with blogs, instant messaging, and Web-based journals, you can start to understand what makes Twitter so unique. The Web offers a lot of information. Twitter can turn those long articles, lengthy conversations, and far-reaching connections into easily digestible facts, thoughts, questions, ideas, concepts, and sound bites. In other words, when you have only 140 characters, you have to be succinct.

Looking at Twitter for the first time, you might be compelled to ask, "But why are all these people, many of whom seem like just random strangers, talking?" At first glance, Twitter seems flooded with disjointed conversations, interactions, and information. You can find news headlines, political debates, observations on the weather, and requests for advice. The idea of Twitter can be a bit confusing for new twitterers (people who use Twitter).

People have many reasons for using Twitter:

Twitter is pretty easy to actually use, meaning everyone from your 8-year-old cousin to your 92-year-old great-grandma can figure out how to use Twitter and say hello. Because you can access Twitter by using either a computer or cellphone (or both!), it fits into mobile lifestyles and brings you closer to the everyday thoughts of those you're interested in.

Barack Obama's successful presidential campaign in 2008 was perhaps the best example of an organization using Twitter to solicit donations, raise awareness, and call people to action. During the campaign, tens of thousands of Twitter users followed Barack Obama at http://twitter.com/barackobama, where campaign staff used the service to provide the then-candidate's whereabouts on the trail and kick off new donation initiatives. (Even though election laws mean the account can no longer be updated, it has hundreds of thousands of followers at the time of this writing.)

The power of Twitter works for much smaller organizations, too. Groups such as churches and local charities can use Twitter to provide an additional way for members to connect, plan, and reach out beyond their immediate community. Preachers tweet about their planned sermons, youth group directors tweet about events, and local soup kitchens tweet when they need help. Whether it's extra hands for a project, far-reaching assistance with a fundraiser, or some other big idea, Twitter can enable organizations operating on a budget to think on their feet.

New organizations have also sprung up through Twitter. Some people have started their own donation campaigns on Twitter and encouraged other Twitter users to donate and then tweet about it. But Twitter isn't just for charities. Enthusiasts of just about any interest have banded together on Twitter. For example, you can find organizations for food and wine lovers, sharing recipes and swapping restaurant reviews on Twitter. (You can search for the subjects that interest you on http://search.twitter.com.)

For example, musicians use Twitter to spread the word about concerts, song releases, charitable efforts, and their daily lives as celebrities. (Even Britney Spears has an official Twitter account: @BritneySpears.) John Mayer (@JohnCMayer) live-tweeted from the GRAMMY Awards. Musicians working hard to make a name have used Twitter to engage thriving, and involved, fan bases.

Twitter has also been a big help for community efforts. Whether it's Amber Alerts, fundraisers, searching for kidney donors, or rescuing James Buck from an Egyptian jail (http://twitter.com/jamesbuck/statuses/786571964), Twitter has shone as a tool for social good. Plenty of people in the world want to lend a helping hand, and Twitter's platform makes it easy, in real time, with a global network of connections.

Discount airline JetBlue uses Twitter to advertise fare specials, put out weather alerts, and conduct customer service (http://twitter.com/jetblue). Coffee retailer Starbucks uses Twitter to connect with customers and spread company culture (http://twitter.com/starbucks), as does online shoe retailer Zappos.com (http://twitter.com/zappos). Early on, computer manufacturer Dell started a Twitter account (http://twitter.com/delloutlet) to promote special deals on returned equipment. It announced in December 2008 that its Twitter account has generated over a million dollars in revenue. Predictably, Dell now has many more accounts: www.dell.com/twitter.

So why would a business want to establish a presence on Twitter?

But none of these reasons really scratch the surface of why so many people use Twitter. Whether you want to use it for mostly personal or mostly business reasons, or even a blend of the two, you'll find that your reasons for tweeting multiply over time while Twitter becomes more and more useful to you. Each chapter in this book clearly explains why Twitter has caught on like wildfire and how you can join in the fun (and enjoy the business benefits) of this microsharing service.

When you log into Twitter, a question appears in large print across the top of the screen: "What's Happening?" The most basic activity on Twitter is to answer that question, whenever and however you feel like it. The beauty of this simple question is that you can answer it in so many different ways, and your answer can spark so many conversations.

Instead of "What's Happening?", Twitter's prompt used to be "What are you doing?" As more people were using Twitter, the company realized that many of its users were ignoring the former question and instead reported on things more interesting to them, not necessarily about what they were doing. To that end, Twitter is inherently flexible and open-ended, so you don't need to stick to a rigid set of rules. In effect, Twitter is what you make it. Feel free to tell us what you're doing.

Sometimes, the Twitter prompt has users stuck in a rut, freezing up out of self-consciousness, concerned that they're not doing it right, or are stuck with just plain old 140-character writer's block. You know these Twitter accounts when you see them: The twitterers end up twittering only about what they had for breakfast, that they're leaving the office to go home and watch 24, or various other mundane life updates that don't spark much conversation. Many of these Twitter users don't end up getting involved in the Twitter culture, and some then stop using Twitter altogether.

Simply put, a tweet is what you call the 140-character message that you send out onto the Web by using Twitter.

Why call it a tweet? It's convenient, tying into the whole theme of birds chirping. Also, like much of the Twitter vocabulary, tweet is a term coined by the users, rather than the company — evidence of the playful loyalty that avid users have with the Twitter brand. In fact, it wasn't until late Winter 2010 that Twitter officially adjusted updates to tweets, based on how the world talked about tweeting.

Twitter limits the length of tweets to 140 characters (letters, numbers, symbols, and spaces), a length that may seem short at first. And it is. How in the heck are you supposed to say anything in this tiny bit of space? How can you distill your company pitch into 140 characters, review a book, or summarize a movie in so few words? With time, you get used to this length restriction. Perhaps one of the coolest things about Twitter is that the more you use it, the easier it is to write short, sharp, clear tweets. As you get more accustomed to tweeting, you find that squeezing thoughts into 140 characters often makes you refine the point in ways you wouldn't have thought of before.

At the risk of sounding like a Twitter cheerleader, don't ask "What can you do with Twitter?" Instead, ask yourself, "What can't you do with Twitter?" From its inception, Twitter has had a very open application program interface (API), which is the geek-speak term for code that lets external developers and programmers weave the Twitter service and functions into other applications and services on the Web. The open nature of the Twitter API has led some people to come up with very interesting uses for Twitter.

The most popular Twitter applications are downloadable client programs that let you manage and update your Twitter feed from your desktop; vying for most popular are TweetDeck (www.tweetdeck.com), Seesmic (www.seesmic.com), Twhirl (http://www.twhirl.org/), and Tweetie, (www.atebits.com/tweetie), but people access Twitter dozens of ways, including (about half of average use) Twitter.com.

On the iPhone, Tweetie 2 became such a dominant player, Twitter Inc. acquired the company as of April of 2010. By the time this reaches print, it should be the company's official iPhone Twitter client.

Thousands of tools already exist. Some are incredibly useful, like Co-tweet and HootSuite which help you manage multiple accounts and a lot of information, while others help you integrate with other social networks, like FourSquare or Facebook. (We cover these tools in Chapter 9.) The beauty of Twitter means that any application can be beneficial if Twitter users respond to it. Because Twitter can do so much, so simply, the array of third-party applications offers a nice balance of work and play.

If you want to stick with using Twitter just as a status update service, that's fine. In fact, many people do. But if you want to really maximize your use of Twitter, you may want to check out all the neat ways you can use it — for example, to track expenses, request restaurant reviews, follow gas prices, read the news, find out the weather in your area, give hurricane relief to people in need, fundraise, drive cancer awareness, and a whole lot more. This diversity of use makes Twitter a vibrant community that you can tap into both for fun and for business.