NEW YORK: With Twitter in the news because of a public stock offering, you might be deciding it's finally time to start tweeting.

But what exactly is Twitter, a tweet and the etiquette for using the popular communication tool?

Here are the basics. Keep in mind that the company's service isn't expected to change in the short term after it starts trading publicly Thursday. Twitter is pricing its initial public offering of stock at $26, valuing the company at more than $18 billion. It's the most-anticipated IPO since Facebook went public last year.

To begin your presence on Twitter, you first need an account, which is free. Go to Twitter.com or its mobile app to create one. Pick a username, or handle, which is how people will refer to you. Try to find something unique that tells the world a little bit about you. I like to travel, so I picked (at)GlobeTrotScott as my handle.

Once the account is set up, just click in the box that says "Compose new Tweet..." and type whatever is on your mind, up to 140 characters. On the mobile app, look for the small box with the feather to compose your tweet.

But Twitter isn't just about broadcasting what you had for lunch - though you can do that. It's about learning what other people are up to. You can start following other people by using the "find friends" feature. You can also search for various celebrities, news sites or whatever else might catch your interest.

You don't have to know somebody to follow that person. Just click the little follow button. It's very voyeuristic.

This is probably a good point to talk about privacy. There really isn't any on Twitter. Unless you lock your account, anybody can follow you and see what you have tweeted. And those you follow know that you are following them. (As for locking your account, you can do that by checking "Protect my Tweets" in the settings, but that defeats the point of Twitter, which is to give you an audience for your musings, whether brilliant or inane.)

There are a few ways to engage in a conversation on Twitter.

The first is to just mention somebody in a tweet. Just precede the Twitter handle with the "at" symbol. For instance: "It was nice to catch up with (at)GlobeTrotScott today." If you want to be fancy, throw in a reference to the bar you were at: "It was nice to catch up with (at)GlobeTrotScott today over drinks and snacks (at)TheSpottedPig."

If you mention me in a tweet, I will see it on the (at)Connect tab of Twitter.com or the (at) tab on the mobile app.

You can then reply to the tweet. The person who tweeted and anybody else mentioned in it will see the message in their feeds. But remember: Although it is just aimed at them, anybody on Twitter can see that message.

You can also retweet a message, often referred to as RT. This is a way to share something somebody else posted on Twitter with all of your followers. If you hit the "Retweet" button, it will just repeat the message to your followers. You can also write "RT," copy the person's handle and the message. Feel free to add your own thoughts before the RT to show why you thought it was worth sharing.

Finally, there is a way to send a private tweet - known as a direct message, or DM - to somebody following you. The easiest way to do it is to go to that person's profile summary. On the pull down menu next to "following," there is an option to send a direct message. You can also just start a tweet with "d" and then a person's handle, and it will send a direct message. You want to make sure you do this right: Anthony Weiner resigned from Congress after sending a sexually suggestive message that he thought was private. It wasn't.

As you start following more and more people, it might be hard to keep up with all their tweets. Enter TweetDeck and HootSuite. Their websites and apps let you customize your Twitter feeds to sort through all the noise. You can create a stream of tweets from your friends, another from news sources, another for sports and another from celebrities. Separate work from fun.

A few other key points. When adding a link to a tweet, first shorten it through a site such as bit.ly. That way your tweet won't go over the 140 characters, and it will look cleaner, too. You can also add a photo to your tweet by clicking on the little camera icon. A link to the image will then be added to your message. But remember, that link takes up precious characters, so keep the message short.

Finally, let's talk about hashtags. They are meant to bring together several tweets on the same topic. So at the end of baseball season, you might see many tweets including (hash)WorldSeries or on Thanksgiving you might see (hash)TurkeyDay (hash)Thankful (hash)Sleepy. Yes, people do tend to string hashtags together.

Just don't do too many. It's looked down upon and then your tweet will (hash)Fail.