Here at Obsessable, we're big fans of micro-blogging website and service, Twitter. If you already know what Twitter is and what it's all about, then make sure you follow us on Twitter and feel free to make suggestions or ask us questions via the service. If you are not familiar with Twitter, or you've heard of it, but never used it, this quick introduction should help you understand what Twitter is, what it's about, and how you may just find it useful.

What is Twitter in 140 characters or less?

Twitter is a microblogging service and a communication tool accessible via the web or your cellphone and it integrates with SMS.

Can you explain that a bit more? Why'd you use less than 140 characters?

If you go to Twitter, you'll see a screen asking you to create an account and explaining in over 140 characters: "Twitter is a service for friends, family, and co–workers to communicate and stay connected through the exchange of quick, frequent answers to one simple question: What are you doing?" They even have a nice video that Common Craft put together called Twitter in Plain English explaining the service (embedded below):

Both Twitter's official description and the video above cover the very basic "What are you doing?" main purpose of Twitter, but they also both sidestep its usefulness a bit and fail to highlight the portability, and therefore the potential power, of the service.

Twitter has a 140 character limit so that the messages can also be sent via SMS to your cell phone if you so choose (and if you're in the U.S., Canada, or India; sorry everywhere else). You can also set Twitter preferences so that any SMS messages from your phone number will post to your Twitter account where others can read what you are doing. You can reply to a specific Twitter user by placing a @ before that person's Twitter username and you can send direct messages to that person by typing dm followed by that person's twitter name. You can also set preferences so that all direct messages sent to your Twitter name are forwarded to your cell phone as an SMS.

Okay, that's cool, I guess, but how is it useful? Why would I want to use Twitter?

Twitter works largely by following other Twitter users and by being followed by other Twitter users. If you and your friends all sign up for Twitter and follow each other (simply visit a person's Twitter page and click the follow button underneath that person's Twitter name while logged in to follow him/her), you can use Twitter to quickly communicate to more than one person. Rather than sending a text message to every one of your friends telling them "We're meeting at the restaurant at 7pm," you can simply send an SMS to your Twitter saying "We're meeting at the restaurant at 7pm" and all your friends will see your note in their individual Twitter streams (the stream of messages from you and all the Twitter users you follow) and if they have your messages set to send an SMS message to their phones, they'll receive the note directly on their mobile phones.

Anything you send over Twitter, however, is public, and you should keep that in mind. Every single tweet (that's what a single message on Twitter is called) appears in the Twitter public timeline and is searchable, unless it's a direct message, and even then, there is some risk of the tweeted information becoming publicly available. There are several sites that take advantage of what people are publicly tweeting, so you should keep that in mind. For example, the site Curse Bird presents a real time feed of all the tweets containing curse words from people swearing on Twitter.

You can also use Twitter to follow what interesting people are talking about and to engage in conversations. If you like all the content here on Obsessable, you can follow Obsessable on Twitter to receive notifications of all of our featured stories. You can also ask us questions, like "@obsessable what's the best netbook for me to buy?" and we'll try to point you in the right direction. You can also follow ObsessableNews to receive notifications of every story that goes out in our newsfeed. This isn't specific to us either. There are plenty of sites, like the New York Times and the BBC, that have some sort of presence on Twitter that you can follow to receive broadcast updates from and you can even interact with some of them.

If you have a decent number of Twitter followers, you can normally ask a question like "What's a good inexpensive Thai restaurant in midtown Manhattan?" and one (if not more) of your followers will answer your question. Sometimes your questions will be met with silence too, but I've been surprised numerous times by the helpful answers I've received by simply asking the question publicly over Twitter.

Even if you want to broadcast information to someone who doesn't use Twitter, Twitter can be useful. Your updates have an RSS feed, so people outside of Twitter can subscribe to them. If you have a blog, there are plugins available for blogging platforms like WordPress that will syndicate your Tweets into the sidebar of your blog. For example, neither of my parents use Twitter, but they follow what I'm up to each day by reading my Twitter stream in the sidebar of my blog.

Recently, Twitter has become more and more useful not only for following breaking news, but for participating in breaking news. Being able to quickly send a text message broadcast to Twitter from his cell phone managed to help James Karl Buck be freed from Egyptian jail. Also, news of a recent Denver plane crash first broke by a passenger on board the plane who Twittered a tweet that no doubt appeared on Curse Bird announcing that he'd just been in a plane crash.

This has just been a brief overview of Twitter for the uninitiated. If you've not tried out Twitter before, sign up for an account (it's free) and let us know what you think in the comments below or by sending us a message @obsessable on Twitter itself. We'll revisit the topic of Twitter soon with discussions of what tools can make the most out of Twitter and how you can use it for various things beyond the few examples provided here. If you have any questions you'd like us to address in future pieces about Twitter, please let us know.