For most of history, "tweet" has been the sound a bird makes. However, with the advent of Twitter, the word "tweet" has taken on a whole new meaning.
A tweet is an online posting, or "micro-blog" created by a Twitter user. The purpose of each tweet is to answer the question, "What are you doing?" However, tweets can contain any information you want to post, such as your plans for the weekend, your thoughts about a TV show, or even notes from a lecture. You can publish a tweet using a computer or a mobile phone. Once published, the tweet will appear on the Twitter home pages of all the users that are following you. Likewise, your Twitter home page will display the most recent tweets of the users that you are following.
Each tweet is limited to 140 characters or less. This limit makes it possible to show several tweets on one page without certain tweets taking up a lot more space than others. However, it also means that tweets must be brief, so you must choose your words wisely. Of course, there is no limit to how many tweets you can post, so if you really have a lot to say, you can publish several tweets in a row. After all, what better way to spend your time than to let the world know that you are at Starbucks, drinking a Frappuccino and reading the latest issue of TIME magazine. That is important information to share with the world.